Auto merge of #2773 - RalfJung:rustup, r=RalfJung

Rustup

.github/ISSUE_TEMPLATE/ice.md

@@ -0,0 +1,49 @@
+---
+name: Internal Compiler Error
+about: Create a report for an internal compiler error in rustc.
+labels: C-bug, I-ICE, T-compiler
+---
+<!--
+Thank you for finding an Internal Compiler Error! 🧊  If possible, try to provide
+a minimal verifiable example. You can read "Rust Bug Minimization Patterns" for
+how to create smaller examples.
+http://blog.pnkfx.org/blog/2019/11/18/rust-bug-minimization-patterns/
+-->
+
+### Code
+
+```Rust
+<code>
+```
+
+
+### Meta
+<!--
+If you're using the stable version of the compiler, you should also check if the
+bug also exists in the beta or nightly versions.
+-->
+
+`rustc --version --verbose`:
+```
+<version>
+```
+
+### Error output
+
+```
+<output>
+```
+
+<!--
+Include a backtrace in the code block by setting `RUST_BACKTRACE=1` in your
+environment. E.g. `RUST_BACKTRACE=1 cargo build`.
+-->
+<details><summary><strong>Backtrace</strong></summary>
+<p>
+
+```
+<backtrace>
+```
+
+</p>
+</details>

.github/ISSUE_TEMPLATE/ice.yaml

@@ -1,5 +1,5 @@
-name: Internal Compiler Error
-description: Create a report for an internal compiler error in `rustc`
+name: Internal Compiler Error (Structured form)
+description: For now, you'll want to use the other ICE template, as GitHub forms have strict limits on the size of fields so backtraces cannot be pasted directly.
 labels: ["C-bug", "I-ICE", "T-compiler"]
 title: "[ICE]: "
 body:
@@ -79,4 +79,4 @@ body:
       label: Anything else?
       description: If you have more details you want to give us to reproduce this issue, please add it here
     validations:
-      required: false
+      required: false

Cargo.lock

@@ -342,7 +342,7 @@ dependencies = [
 
 [[package]]
 name = "cargo"
-version = "0.69.0"
+version = "0.70.0"
 dependencies = [
  "anyhow",
  "base64",

compiler/rustc_abi/src/lib.rs

@@ -1456,6 +1456,8 @@ pub enum PointerKind {
     UniqueOwned,
 }
 
+/// Note that this information is advisory only, and backends are free to ignore it.
+/// It can only be used to encode potential optimizations, but no critical information.
 #[derive(Copy, Clone, Debug)]
 pub struct PointeeInfo {
     pub size: Size,

compiler/rustc_ast/src/util/comments.rs

@@ -58,23 +58,24 @@ pub fn beautify_doc_string(data: Symbol, kind: CommentKind) -> Symbol {
         // In case we have doc comments like `/**` or `/*!`, we want to remove stars if they are
         // present. However, we first need to strip the empty lines so they don't get in the middle
         // when we try to compute the "horizontal trim".
-        let lines = if kind == CommentKind::Block {
-            // Whatever happens, we skip the first line.
-            let mut i = lines
-                .get(0)
-                .map(|l| if l.trim_start().starts_with('*') { 0 } else { 1 })
-                .unwrap_or(0);
-            let mut j = lines.len();
+        let lines = match kind {
+            CommentKind::Block => {
+                // Whatever happens, we skip the first line.
+                let mut i = lines
+                    .get(0)
+                    .map(|l| if l.trim_start().starts_with('*') { 0 } else { 1 })
+                    .unwrap_or(0);
+                let mut j = lines.len();
 
-            while i < j && lines[i].trim().is_empty() {
-                i += 1;
+                while i < j && lines[i].trim().is_empty() {
+                    i += 1;
+                }
+                while j > i && lines[j - 1].trim().is_empty() {
+                    j -= 1;
+                }
+                &lines[i..j]
             }
-            while j > i && lines[j - 1].trim().is_empty() {
-                j -= 1;
-            }
-            &lines[i..j]
-        } else {
-            lines
+            CommentKind::Line => lines,
         };
 
         for line in lines {

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -131,7 +131,7 @@ pub fn print_crate<'a>(
 
         // Currently, in Rust 2018 we don't have `extern crate std;` at the crate
         // root, so this is not needed, and actually breaks things.
-        if edition == Edition::Edition2015 {
+        if edition.rust_2015() {
             // `#![no_std]`
             let fake_attr = attr::mk_attr_word(g, ast::AttrStyle::Inner, sym::no_std, DUMMY_SP);
             s.print_attribute(&fake_attr);

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -344,7 +344,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     } else {
                         err.span_help(source_info.span, "try removing `&mut` here");
                     }
-                } else if decl.mutability == Mutability::Not {
+                } else if decl.mutability.is_not() {
                     if matches!(
                         decl.local_info,
                         Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(

compiler/rustc_borrowck/src/diagnostics/region_name.rs

@@ -187,6 +187,12 @@ impl Display for RegionName {
     }
 }
 
+impl rustc_errors::IntoDiagnosticArg for RegionName {
+    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+        self.to_string().into_diagnostic_arg()
+    }
+}
+
 impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
     pub(crate) fn mir_def_id(&self) -> hir::def_id::LocalDefId {
         self.body.source.def_id().expect_local()

compiler/rustc_borrowck/src/nll.rs

@@ -369,6 +369,8 @@ pub(super) fn dump_mir_results<'tcx>(
     };
 }
 
+#[allow(rustc::diagnostic_outside_of_impl)]
+#[allow(rustc::untranslatable_diagnostic)]
 pub(super) fn dump_annotation<'tcx>(
     infcx: &InferCtxt<'tcx>,
     body: &Body<'tcx>,

compiler/rustc_borrowck/src/session_diagnostics.rs

@@ -1,4 +1,4 @@
-use rustc_errors::{IntoDiagnosticArg, MultiSpan};
+use rustc_errors::MultiSpan;
 use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_middle::ty::{GenericArg, Ty};
 use rustc_span::Span;
@@ -128,18 +128,6 @@ pub(crate) enum LifetimeReturnCategoryErr<'a> {
     },
 }
 
-impl IntoDiagnosticArg for &RegionName {
-    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
-        format!("{}", self).into_diagnostic_arg()
-    }
-}
-
-impl IntoDiagnosticArg for RegionName {
-    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
-        format!("{}", self).into_diagnostic_arg()
-    }
-}
-
 #[derive(Subdiagnostic)]
 pub(crate) enum RequireStaticErr {
     #[note(borrowck_used_impl_require_static)]

compiler/rustc_borrowck/src/type_check/canonical.rs

@@ -181,9 +181,6 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         user_ty: ty::UserType<'tcx>,
         span: Span,
     ) {
-        // FIXME: Ideally MIR types are normalized, but this is not always true.
-        let mir_ty = self.normalize(mir_ty, Locations::All(span));
-
         self.fully_perform_op(
             Locations::All(span),
             ConstraintCategory::Boring,
@@ -217,7 +214,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             return;
         }
 
+        // FIXME: Ideally MIR types are normalized, but this is not always true.
         let mir_ty = self.normalize(mir_ty, Locations::All(span));
+
         let cause = ObligationCause::dummy_with_span(span);
         let param_env = self.param_env;
         let op = |infcx: &'_ _| {

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -2028,7 +2028,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                             }
                         };
 
-                        if ty_to_mut == Mutability::Mut && ty_mut == Mutability::Not {
+                        if ty_to_mut.is_mut() && ty_mut.is_not() {
                             span_mirbug!(
                                 self,
                                 rvalue,

compiler/rustc_codegen_gcc/src/lib.rs

@@ -200,6 +200,7 @@ unsafe impl Sync for GccContext {}
 impl WriteBackendMethods for GccCodegenBackend {
     type Module = GccContext;
     type TargetMachine = ();
+    type TargetMachineError = ();
     type ModuleBuffer = ModuleBuffer;
     type ThinData = ();
     type ThinBuffer = ThinBuffer;

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -1,5 +1,7 @@
 use crate::back::write::{self, save_temp_bitcode, DiagnosticHandlers};
-use crate::errors::DynamicLinkingWithLTO;
+use crate::errors::{
+    DynamicLinkingWithLTO, LlvmError, LtoBitcodeFromRlib, LtoDisallowed, LtoDylib,
+};
 use crate::llvm::{self, build_string};
 use crate::{LlvmCodegenBackend, ModuleLlvm};
 use object::read::archive::ArchiveFile;
@@ -77,15 +79,12 @@ fn prepare_lto(
         // Make sure we actually can run LTO
         for crate_type in cgcx.crate_types.iter() {
             if !crate_type_allows_lto(*crate_type) {
-                let e = diag_handler.fatal(
-                    "lto can only be run for executables, cdylibs and \
-                                            static library outputs",
-                );
-                return Err(e);
+                diag_handler.emit_err(LtoDisallowed);
+                return Err(FatalError);
             } else if *crate_type == CrateType::Dylib {
                 if !cgcx.opts.unstable_opts.dylib_lto {
-                    return Err(diag_handler
-                        .fatal("lto cannot be used for `dylib` crate type without `-Zdylib-lto`"));
+                    diag_handler.emit_err(LtoDylib);
+                    return Err(FatalError);
                 }
             }
         }
@@ -127,7 +126,10 @@ fn prepare_lto(
                         let module = SerializedModule::FromRlib(data.to_vec());
                         upstream_modules.push((module, CString::new(name).unwrap()));
                     }
-                    Err(msg) => return Err(diag_handler.fatal(&msg)),
+                    Err(e) => {
+                        diag_handler.emit_err(e);
+                        return Err(FatalError);
+                    }
                 }
             }
         }
@@ -140,7 +142,7 @@ fn prepare_lto(
     Ok((symbols_below_threshold, upstream_modules))
 }
 
-fn get_bitcode_slice_from_object_data(obj: &[u8]) -> Result<&[u8], String> {
+fn get_bitcode_slice_from_object_data(obj: &[u8]) -> Result<&[u8], LtoBitcodeFromRlib> {
     let mut len = 0;
     let data =
         unsafe { llvm::LLVMRustGetBitcodeSliceFromObjectData(obj.as_ptr(), obj.len(), &mut len) };
@@ -155,8 +157,9 @@ fn get_bitcode_slice_from_object_data(obj: &[u8]) -> Result<&[u8], String> {
         Ok(bc)
     } else {
         assert!(len == 0);
-        let msg = llvm::last_error().unwrap_or_else(|| "unknown LLVM error".to_string());
-        Err(format!("failed to get bitcode from object file for LTO ({})", msg))
+        Err(LtoBitcodeFromRlib {
+            llvm_err: llvm::last_error().unwrap_or_else(|| "unknown LLVM error".to_string()),
+        })
     }
 }
 
@@ -328,10 +331,9 @@ fn fat_lto(
                 });
             info!("linking {:?}", name);
             let data = bc_decoded.data();
-            linker.add(data).map_err(|()| {
-                let msg = format!("failed to load bitcode of module {:?}", name);
-                write::llvm_err(diag_handler, &msg)
-            })?;
+            linker
+                .add(data)
+                .map_err(|()| write::llvm_err(diag_handler, LlvmError::LoadBitcode { name }))?;
             serialized_bitcode.push(bc_decoded);
         }
         drop(linker);
@@ -489,7 +491,7 @@ fn thin_lto(
             symbols_below_threshold.as_ptr(),
             symbols_below_threshold.len() as u32,
         )
-        .ok_or_else(|| write::llvm_err(diag_handler, "failed to prepare thin LTO context"))?;
+        .ok_or_else(|| write::llvm_err(diag_handler, LlvmError::PrepareThinLtoContext))?;
 
         let data = ThinData(data);
 
@@ -562,8 +564,7 @@ fn thin_lto(
         // session, overwriting the previous serialized data (if any).
         if let Some(path) = key_map_path {
             if let Err(err) = curr_key_map.save_to_file(&path) {
-                let msg = format!("Error while writing ThinLTO key data: {}", err);
-                return Err(write::llvm_err(diag_handler, &msg));
+                return Err(write::llvm_err(diag_handler, LlvmError::WriteThinLtoKey { err }));
             }
         }
 
@@ -689,8 +690,7 @@ pub unsafe fn optimize_thin_module(
 
     let module_name = &thin_module.shared.module_names[thin_module.idx];
     let tm_factory_config = TargetMachineFactoryConfig::new(cgcx, module_name.to_str().unwrap());
-    let tm =
-        (cgcx.tm_factory)(tm_factory_config).map_err(|e| write::llvm_err(&diag_handler, &e))?;
+    let tm = (cgcx.tm_factory)(tm_factory_config).map_err(|e| write::llvm_err(&diag_handler, e))?;
 
     // Right now the implementation we've got only works over serialized
     // modules, so we create a fresh new LLVM context and parse the module
@@ -717,8 +717,7 @@ pub unsafe fn optimize_thin_module(
         let mut cu2 = ptr::null_mut();
         llvm::LLVMRustThinLTOGetDICompileUnit(llmod, &mut cu1, &mut cu2);
         if !cu2.is_null() {
-            let msg = "multiple source DICompileUnits found";
-            return Err(write::llvm_err(&diag_handler, msg));
+            return Err(write::llvm_err(&diag_handler, LlvmError::MultipleSourceDiCompileUnit));
         }
 
         // Up next comes the per-module local analyses that we do for Thin LTO.
@@ -733,8 +732,7 @@ pub unsafe fn optimize_thin_module(
             let _timer =
                 cgcx.prof.generic_activity_with_arg("LLVM_thin_lto_rename", thin_module.name());
             if !llvm::LLVMRustPrepareThinLTORename(thin_module.shared.data.0, llmod, target) {
-                let msg = "failed to prepare thin LTO module";
-                return Err(write::llvm_err(&diag_handler, msg));
+                return Err(write::llvm_err(&diag_handler, LlvmError::PrepareThinLtoModule));
             }
             save_temp_bitcode(cgcx, &module, "thin-lto-after-rename");
         }
@@ -744,8 +742,7 @@ pub unsafe fn optimize_thin_module(
                 .prof
                 .generic_activity_with_arg("LLVM_thin_lto_resolve_weak", thin_module.name());
             if !llvm::LLVMRustPrepareThinLTOResolveWeak(thin_module.shared.data.0, llmod) {
-                let msg = "failed to prepare thin LTO module";
-                return Err(write::llvm_err(&diag_handler, msg));
+                return Err(write::llvm_err(&diag_handler, LlvmError::PrepareThinLtoModule));
             }
             save_temp_bitcode(cgcx, &module, "thin-lto-after-resolve");
         }
@@ -755,8 +752,7 @@ pub unsafe fn optimize_thin_module(
                 .prof
                 .generic_activity_with_arg("LLVM_thin_lto_internalize", thin_module.name());
             if !llvm::LLVMRustPrepareThinLTOInternalize(thin_module.shared.data.0, llmod) {
-                let msg = "failed to prepare thin LTO module";
-                return Err(write::llvm_err(&diag_handler, msg));
+                return Err(write::llvm_err(&diag_handler, LlvmError::PrepareThinLtoModule));
             }
             save_temp_bitcode(cgcx, &module, "thin-lto-after-internalize");
         }
@@ -765,8 +761,7 @@ pub unsafe fn optimize_thin_module(
             let _timer =
                 cgcx.prof.generic_activity_with_arg("LLVM_thin_lto_import", thin_module.name());
             if !llvm::LLVMRustPrepareThinLTOImport(thin_module.shared.data.0, llmod, target) {
-                let msg = "failed to prepare thin LTO module";
-                return Err(write::llvm_err(&diag_handler, msg));
+                return Err(write::llvm_err(&diag_handler, LlvmError::PrepareThinLtoModule));
             }
             save_temp_bitcode(cgcx, &module, "thin-lto-after-import");
         }
@@ -886,11 +881,7 @@ pub fn parse_module<'a>(
     diag_handler: &Handler,
 ) -> Result<&'a llvm::Module, FatalError> {
     unsafe {
-        llvm::LLVMRustParseBitcodeForLTO(cx, data.as_ptr(), data.len(), name.as_ptr()).ok_or_else(
-            || {
-                let msg = "failed to parse bitcode for LTO module";
-                write::llvm_err(diag_handler, msg)
-            },
-        )
+        llvm::LLVMRustParseBitcodeForLTO(cx, data.as_ptr(), data.len(), name.as_ptr())
+            .ok_or_else(|| write::llvm_err(diag_handler, LlvmError::ParseBitcode))
     }
 }

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -5,6 +5,9 @@ use crate::back::profiling::{
 use crate::base;
 use crate::common;
 use crate::consts;
+use crate::errors::{
+    CopyBitcode, FromLlvmDiag, FromLlvmOptimizationDiag, LlvmError, WithLlvmError, WriteBytecode,
+};
 use crate::llvm::{self, DiagnosticInfo, PassManager};
 use crate::llvm_util;
 use crate::type_::Type;
@@ -37,10 +40,10 @@ use std::slice;
 use std::str;
 use std::sync::Arc;
 
-pub fn llvm_err(handler: &rustc_errors::Handler, msg: &str) -> FatalError {
+pub fn llvm_err<'a>(handler: &rustc_errors::Handler, err: LlvmError<'a>) -> FatalError {
     match llvm::last_error() {
-        Some(err) => handler.fatal(&format!("{}: {}", msg, err)),
-        None => handler.fatal(msg),
+        Some(llvm_err) => handler.emit_almost_fatal(WithLlvmError(err, llvm_err)),
+        None => handler.emit_almost_fatal(err),
     }
 }
 
@@ -85,10 +88,9 @@ pub fn write_output_file<'ll>(
             }
         }
 
-        result.into_result().map_err(|()| {
-            let msg = format!("could not write output to {}", output.display());
-            llvm_err(handler, &msg)
-        })
+        result
+            .into_result()
+            .map_err(|()| llvm_err(handler, LlvmError::WriteOutput { path: output }))
     }
 }
 
@@ -98,7 +100,7 @@ pub fn create_informational_target_machine(sess: &Session) -> &'static mut llvm:
     // system/tcx is set up.
     let features = llvm_util::global_llvm_features(sess, false);
     target_machine_factory(sess, config::OptLevel::No, &features)(config)
-        .unwrap_or_else(|err| llvm_err(sess.diagnostic(), &err).raise())
+        .unwrap_or_else(|err| llvm_err(sess.diagnostic(), err).raise())
 }
 
 pub fn create_target_machine(tcx: TyCtxt<'_>, mod_name: &str) -> &'static mut llvm::TargetMachine {
@@ -117,7 +119,7 @@ pub fn create_target_machine(tcx: TyCtxt<'_>, mod_name: &str) -> &'static mut ll
         tcx.backend_optimization_level(()),
         tcx.global_backend_features(()),
     )(config)
-    .unwrap_or_else(|err| llvm_err(tcx.sess.diagnostic(), &err).raise())
+    .unwrap_or_else(|err| llvm_err(tcx.sess.diagnostic(), err).raise())
 }
 
 pub fn to_llvm_opt_settings(
@@ -240,9 +242,7 @@ pub fn target_machine_factory(
             )
         };
 
-        tm.ok_or_else(|| {
-            format!("Could not create LLVM TargetMachine for triple: {}", triple.to_str().unwrap())
-        })
+        tm.ok_or_else(|| LlvmError::CreateTargetMachine { triple: triple.clone() })
     })
 }
 
@@ -355,25 +355,28 @@ unsafe extern "C" fn diagnostic_handler(info: &DiagnosticInfo, user: *mut c_void
             };
 
             if enabled {
-                diag_handler.note_without_error(&format!(
-                    "{}:{}:{}: {}: {}",
-                    opt.filename, opt.line, opt.column, opt.pass_name, opt.message,
-                ));
+                diag_handler.emit_note(FromLlvmOptimizationDiag {
+                    filename: &opt.filename,
+                    line: opt.line,
+                    column: opt.column,
+                    pass_name: &opt.pass_name,
+                    message: &opt.message,
+                });
             }
         }
         llvm::diagnostic::PGO(diagnostic_ref) | llvm::diagnostic::Linker(diagnostic_ref) => {
-            let msg = llvm::build_string(|s| {
+            let message = llvm::build_string(|s| {
                 llvm::LLVMRustWriteDiagnosticInfoToString(diagnostic_ref, s)
             })
             .expect("non-UTF8 diagnostic");
-            diag_handler.warn(&msg);
+            diag_handler.emit_warning(FromLlvmDiag { message });
         }
         llvm::diagnostic::Unsupported(diagnostic_ref) => {
-            let msg = llvm::build_string(|s| {
+            let message = llvm::build_string(|s| {
                 llvm::LLVMRustWriteDiagnosticInfoToString(diagnostic_ref, s)
             })
             .expect("non-UTF8 diagnostic");
-            diag_handler.err(&msg);
+            diag_handler.emit_err(FromLlvmDiag { message });
         }
         llvm::diagnostic::UnknownDiagnostic(..) => {}
     }
@@ -494,7 +497,7 @@ pub(crate) unsafe fn llvm_optimize(
         llvm_plugins.as_ptr().cast(),
         llvm_plugins.len(),
     );
-    result.into_result().map_err(|()| llvm_err(diag_handler, "failed to run LLVM passes"))
+    result.into_result().map_err(|()| llvm_err(diag_handler, LlvmError::RunLlvmPasses))
 }
 
 // Unsafe due to LLVM calls.
@@ -547,8 +550,7 @@ pub(crate) fn link(
         let _timer = cgcx.prof.generic_activity_with_arg("LLVM_link_module", &*module.name);
         let buffer = ModuleBuffer::new(module.module_llvm.llmod());
         linker.add(buffer.data()).map_err(|()| {
-            let msg = format!("failed to serialize module {:?}", module.name);
-            llvm_err(diag_handler, &msg)
+            llvm_err(diag_handler, LlvmError::SerializeModule { name: &module.name })
         })?;
     }
     drop(linker);
@@ -626,9 +628,8 @@ pub(crate) unsafe fn codegen(
                 let _timer = cgcx
                     .prof
                     .generic_activity_with_arg("LLVM_module_codegen_emit_bitcode", &*module.name);
-                if let Err(e) = fs::write(&bc_out, data) {
-                    let msg = format!("failed to write bytecode to {}: {}", bc_out.display(), e);
-                    diag_handler.err(&msg);
+                if let Err(err) = fs::write(&bc_out, data) {
+                    diag_handler.emit_err(WriteBytecode { path: &bc_out, err });
                 }
             }
 
@@ -678,10 +679,9 @@ pub(crate) unsafe fn codegen(
                 record_artifact_size(&cgcx.prof, "llvm_ir", &out);
             }
 
-            result.into_result().map_err(|()| {
-                let msg = format!("failed to write LLVM IR to {}", out.display());
-                llvm_err(diag_handler, &msg)
-            })?;
+            result
+                .into_result()
+                .map_err(|()| llvm_err(diag_handler, LlvmError::WriteIr { path: &out }))?;
         }
 
         if config.emit_asm {
@@ -749,8 +749,8 @@ pub(crate) unsafe fn codegen(
 
             EmitObj::Bitcode => {
                 debug!("copying bitcode {:?} to obj {:?}", bc_out, obj_out);
-                if let Err(e) = link_or_copy(&bc_out, &obj_out) {
-                    diag_handler.err(&format!("failed to copy bitcode to object file: {}", e));
+                if let Err(err) = link_or_copy(&bc_out, &obj_out) {
+                    diag_handler.emit_err(CopyBitcode { err });
                 }
 
                 if !config.emit_bc {

compiler/rustc_codegen_llvm/src/context.rs

@@ -150,17 +150,14 @@ pub unsafe fn create_module<'ll>(
             target_data_layout =
                 "e-m:x-p:32:32-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:32-n8:16:32-a:0:32-S32"
                     .to_string();
-        }
-        if sess.target.arch == "wasm32" {
+        } else if sess.target.arch == "wasm32" {
             target_data_layout = target_data_layout.replace("-p10:8:8-p20:8:8", "");
         }
     }
     if llvm_version < (16, 0, 0) {
         if sess.target.arch == "s390x" {
             target_data_layout = target_data_layout.replace("-v128:64", "");
-        }
-
-        if sess.target.arch == "riscv64" {
+        } else if sess.target.arch == "riscv64" {
             target_data_layout = target_data_layout.replace("-n32:64-", "-n64-");
         }
     }

compiler/rustc_codegen_llvm/src/errors.rs

@@ -1,10 +1,11 @@
 use std::borrow::Cow;
+use std::ffi::CString;
+use std::path::Path;
 
-use rustc_errors::fluent;
-use rustc_errors::DiagnosticBuilder;
-use rustc_errors::ErrorGuaranteed;
-use rustc_errors::Handler;
-use rustc_errors::IntoDiagnostic;
+use rustc_data_structures::small_c_str::SmallCStr;
+use rustc_errors::{
+    fluent, DiagnosticBuilder, EmissionGuarantee, ErrorGuaranteed, Handler, IntoDiagnostic,
+};
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::Span;
 
@@ -81,10 +82,18 @@ pub(crate) struct DlltoolFailImportLibrary<'a> {
 #[note]
 pub(crate) struct DynamicLinkingWithLTO;
 
-#[derive(Diagnostic)]
-#[diag(codegen_llvm_fail_parsing_target_machine_config_to_target_machine)]
-pub(crate) struct FailParsingTargetMachineConfigToTargetMachine {
-    pub error: String,
+pub(crate) struct ParseTargetMachineConfig<'a>(pub LlvmError<'a>);
+
+impl<EM: EmissionGuarantee> IntoDiagnostic<'_, EM> for ParseTargetMachineConfig<'_> {
+    fn into_diagnostic(self, sess: &'_ Handler) -> DiagnosticBuilder<'_, EM> {
+        let diag: DiagnosticBuilder<'_, EM> = self.0.into_diagnostic(sess);
+        let (message, _) = diag.styled_message().first().expect("`LlvmError` with no message");
+        let message = sess.eagerly_translate_to_string(message.clone(), diag.args());
+
+        let mut diag = sess.struct_diagnostic(fluent::codegen_llvm_parse_target_machine_config);
+        diag.set_arg("error", message);
+        diag
+    }
 }
 
 pub(crate) struct TargetFeatureDisableOrEnable<'a> {
@@ -110,3 +119,99 @@ impl IntoDiagnostic<'_, ErrorGuaranteed> for TargetFeatureDisableOrEnable<'_> {
         diag
     }
 }
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_lto_disallowed)]
+pub(crate) struct LtoDisallowed;
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_lto_dylib)]
+pub(crate) struct LtoDylib;
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_lto_bitcode_from_rlib)]
+pub(crate) struct LtoBitcodeFromRlib {
+    pub llvm_err: String,
+}
+
+#[derive(Diagnostic)]
+pub enum LlvmError<'a> {
+    #[diag(codegen_llvm_write_output)]
+    WriteOutput { path: &'a Path },
+    #[diag(codegen_llvm_target_machine)]
+    CreateTargetMachine { triple: SmallCStr },
+    #[diag(codegen_llvm_run_passes)]
+    RunLlvmPasses,
+    #[diag(codegen_llvm_serialize_module)]
+    SerializeModule { name: &'a str },
+    #[diag(codegen_llvm_write_ir)]
+    WriteIr { path: &'a Path },
+    #[diag(codegen_llvm_prepare_thin_lto_context)]
+    PrepareThinLtoContext,
+    #[diag(codegen_llvm_load_bitcode)]
+    LoadBitcode { name: CString },
+    #[diag(codegen_llvm_write_thinlto_key)]
+    WriteThinLtoKey { err: std::io::Error },
+    #[diag(codegen_llvm_multiple_source_dicompileunit)]
+    MultipleSourceDiCompileUnit,
+    #[diag(codegen_llvm_prepare_thin_lto_module)]
+    PrepareThinLtoModule,
+    #[diag(codegen_llvm_parse_bitcode)]
+    ParseBitcode,
+}
+
+pub(crate) struct WithLlvmError<'a>(pub LlvmError<'a>, pub String);
+
+impl<EM: EmissionGuarantee> IntoDiagnostic<'_, EM> for WithLlvmError<'_> {
+    fn into_diagnostic(self, sess: &'_ Handler) -> DiagnosticBuilder<'_, EM> {
+        use LlvmError::*;
+        let msg_with_llvm_err = match &self.0 {
+            WriteOutput { .. } => fluent::codegen_llvm_write_output_with_llvm_err,
+            CreateTargetMachine { .. } => fluent::codegen_llvm_target_machine_with_llvm_err,
+            RunLlvmPasses => fluent::codegen_llvm_run_passes_with_llvm_err,
+            SerializeModule { .. } => fluent::codegen_llvm_serialize_module_with_llvm_err,
+            WriteIr { .. } => fluent::codegen_llvm_write_ir_with_llvm_err,
+            PrepareThinLtoContext => fluent::codegen_llvm_prepare_thin_lto_context_with_llvm_err,
+            LoadBitcode { .. } => fluent::codegen_llvm_load_bitcode_with_llvm_err,
+            WriteThinLtoKey { .. } => fluent::codegen_llvm_write_thinlto_key_with_llvm_err,
+            MultipleSourceDiCompileUnit => {
+                fluent::codegen_llvm_multiple_source_dicompileunit_with_llvm_err
+            }
+            PrepareThinLtoModule => fluent::codegen_llvm_prepare_thin_lto_module_with_llvm_err,
+            ParseBitcode => fluent::codegen_llvm_parse_bitcode_with_llvm_err,
+        };
+        let mut diag = self.0.into_diagnostic(sess);
+        diag.set_primary_message(msg_with_llvm_err);
+        diag.set_arg("llvm_err", self.1);
+        diag
+    }
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_from_llvm_optimization_diag)]
+pub(crate) struct FromLlvmOptimizationDiag<'a> {
+    pub filename: &'a str,
+    pub line: std::ffi::c_uint,
+    pub column: std::ffi::c_uint,
+    pub pass_name: &'a str,
+    pub message: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_from_llvm_diag)]
+pub(crate) struct FromLlvmDiag {
+    pub message: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_write_bytecode)]
+pub(crate) struct WriteBytecode<'a> {
+    pub path: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_copy_bitcode)]
+pub(crate) struct CopyBitcode {
+    pub err: std::io::Error,
+}

compiler/rustc_codegen_llvm/src/lib.rs

@@ -5,11 +5,12 @@
 //! This API is completely unstable and subject to change.
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
-#![feature(hash_raw_entry)]
-#![feature(let_chains)]
 #![feature(extern_types)]
-#![feature(once_cell)]
+#![feature(hash_raw_entry)]
 #![feature(iter_intersperse)]
+#![feature(let_chains)]
+#![feature(never_type)]
+#![feature(once_cell)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
 #![deny(rustc::untranslatable_diagnostic)]
@@ -22,7 +23,7 @@ extern crate tracing;
 
 use back::write::{create_informational_target_machine, create_target_machine};
 
-use errors::FailParsingTargetMachineConfigToTargetMachine;
+use errors::ParseTargetMachineConfig;
 pub use llvm_util::target_features;
 use rustc_ast::expand::allocator::AllocatorKind;
 use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
@@ -169,6 +170,7 @@ impl WriteBackendMethods for LlvmCodegenBackend {
     type Module = ModuleLlvm;
     type ModuleBuffer = back::lto::ModuleBuffer;
     type TargetMachine = &'static mut llvm::TargetMachine;
+    type TargetMachineError = crate::errors::LlvmError<'static>;
     type ThinData = back::lto::ThinData;
     type ThinBuffer = back::lto::ThinBuffer;
     fn print_pass_timings(&self) {
@@ -416,8 +418,7 @@ impl ModuleLlvm {
             let tm = match (cgcx.tm_factory)(tm_factory_config) {
                 Ok(m) => m,
                 Err(e) => {
-                    handler.emit_err(FailParsingTargetMachineConfigToTargetMachine { error: e });
-                    return Err(FatalError);
+                    return Err(handler.emit_almost_fatal(ParseTargetMachineConfig(e)));
                 }
             };
 

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -305,8 +305,12 @@ impl TargetMachineFactoryConfig {
 }
 
 pub type TargetMachineFactoryFn<B> = Arc<
-    dyn Fn(TargetMachineFactoryConfig) -> Result<<B as WriteBackendMethods>::TargetMachine, String>
-        + Send
+    dyn Fn(
+            TargetMachineFactoryConfig,
+        ) -> Result<
+            <B as WriteBackendMethods>::TargetMachine,
+            <B as WriteBackendMethods>::TargetMachineError,
+        > + Send
         + Sync,
 >;
 

compiler/rustc_codegen_ssa/src/traits/write.rs

@@ -8,6 +8,7 @@ use rustc_middle::dep_graph::WorkProduct;
 pub trait WriteBackendMethods: 'static + Sized + Clone {
     type Module: Send + Sync;
     type TargetMachine;
+    type TargetMachineError;
     type ModuleBuffer: ModuleBufferMethods;
     type ThinData: Send + Sync;
     type ThinBuffer: ThinBufferMethods;

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -622,10 +622,9 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
         let alloc = alloc.inner();
         if is_write {
             // Write access. These are never allowed, but we give a targeted error message.
-            if alloc.mutability == Mutability::Not {
-                Err(err_ub!(WriteToReadOnly(alloc_id)).into())
-            } else {
-                Err(ConstEvalErrKind::ModifiedGlobal.into())
+            match alloc.mutability {
+                Mutability::Not => Err(err_ub!(WriteToReadOnly(alloc_id)).into()),
+                Mutability::Mut => Err(ConstEvalErrKind::ModifiedGlobal.into()),
             }
         } else {
             // Read access. These are usually allowed, with some exceptions.

compiler/rustc_const_eval/src/interpret/intern.rs

@@ -30,15 +30,15 @@ use super::{
 use crate::const_eval;
 
 pub trait CompileTimeMachine<'mir, 'tcx, T> = Machine<
-    'mir,
-    'tcx,
-    MemoryKind = T,
-    Provenance = AllocId,
-    ExtraFnVal = !,
-    FrameExtra = (),
-    AllocExtra = (),
-    MemoryMap = FxIndexMap<AllocId, (MemoryKind<T>, Allocation)>,
->;
+        'mir,
+        'tcx,
+        MemoryKind = T,
+        Provenance = AllocId,
+        ExtraFnVal = !,
+        FrameExtra = (),
+        AllocExtra = (),
+        MemoryMap = FxIndexMap<AllocId, (MemoryKind<T>, Allocation)>,
+    >;
 
 struct InternVisitor<'rt, 'mir, 'tcx, M: CompileTimeMachine<'mir, 'tcx, const_eval::MemoryKind>> {
     /// The ectx from which we intern.

compiler/rustc_const_eval/src/interpret/memory.rs

@@ -304,7 +304,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             .into());
         };
 
-        if alloc.mutability == Mutability::Not {
+        if alloc.mutability.is_not() {
             throw_ub_format!("deallocating immutable allocation {alloc_id:?}");
         }
         if alloc_kind != kind {
@@ -631,7 +631,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         }
 
         let (_kind, alloc) = self.memory.alloc_map.get_mut(id).unwrap();
-        if alloc.mutability == Mutability::Not {
+        if alloc.mutability.is_not() {
             throw_ub!(WriteToReadOnly(id))
         }
         Ok((alloc, &mut self.machine))

compiler/rustc_const_eval/src/transform/validate.rs

@@ -754,7 +754,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
                 // FIXME(JakobDegen) The validator should check that `self.mir_phase <
                 // DropsLowered`. However, this causes ICEs with generation of drop shims, which
                 // seem to fail to set their `MirPhase` correctly.
-                if *kind == RetagKind::Raw || *kind == RetagKind::TwoPhase {
+                if matches!(kind, RetagKind::Raw | RetagKind::TwoPhase) {
                     self.fail(location, format!("explicit `{:?}` is forbidden", kind));
                 }
             }

compiler/rustc_data_structures/src/obligation_forest/mod.rs

@@ -95,10 +95,7 @@ pub trait ForestObligation: Clone + Debug {
 pub trait ObligationProcessor {
     type Obligation: ForestObligation;
     type Error: Debug;
-    type OUT: OutcomeTrait<
-        Obligation = Self::Obligation,
-        Error = Error<Self::Obligation, Self::Error>,
-    >;
+    type OUT: OutcomeTrait<Obligation = Self::Obligation, Error = Error<Self::Obligation, Self::Error>>;
 
     fn needs_process_obligation(&self, obligation: &Self::Obligation) -> bool;
 

compiler/rustc_driver/src/lib.rs

@@ -43,7 +43,6 @@ use rustc_span::source_map::{FileLoader, FileName};
 use rustc_span::symbol::sym;
 use rustc_target::json::ToJson;
 
-use std::borrow::Cow;
 use std::cmp::max;
 use std::env;
 use std::ffi::OsString;
@@ -1205,29 +1204,20 @@ pub fn report_ice(info: &panic::PanicInfo<'_>, bug_report_url: &str) {
         handler.emit_diagnostic(&mut d);
     }
 
-    let mut xs: Vec<Cow<'static, str>> = vec![
-        "the compiler unexpectedly panicked. this is a bug.".into(),
-        format!("we would appreciate a bug report: {bug_report_url}").into(),
-        format!(
-            "rustc {} running on {}",
-            util::version_str!().unwrap_or("unknown_version"),
-            config::host_triple()
-        )
-        .into(),
-    ];
+    handler.emit_note(session_diagnostics::Ice);
+    handler.emit_note(session_diagnostics::IceBugReport { bug_report_url });
+    handler.emit_note(session_diagnostics::IceVersion {
+        version: util::version_str!().unwrap_or("unknown_version"),
+        triple: config::host_triple(),
+    });
 
     if let Some((flags, excluded_cargo_defaults)) = extra_compiler_flags() {
-        xs.push(format!("compiler flags: {}", flags.join(" ")).into());
-
+        handler.emit_note(session_diagnostics::IceFlags { flags: flags.join(" ") });
         if excluded_cargo_defaults {
-            xs.push("some of the compiler flags provided by cargo are hidden".into());
+            handler.emit_note(session_diagnostics::IceExcludeCargoDefaults);
         }
     }
 
-    for note in &xs {
-        handler.note_without_error(note.as_ref());
-    }
-
     // If backtraces are enabled, also print the query stack
     let backtrace = env::var_os("RUST_BACKTRACE").map_or(false, |x| &x != "0");
 

compiler/rustc_driver/src/session_diagnostics.rs

@@ -38,3 +38,30 @@ pub(crate) struct UnprettyDumpFail {
     pub path: String,
     pub err: String,
 }
+
+#[derive(Diagnostic)]
+#[diag(driver_ice)]
+pub(crate) struct Ice;
+
+#[derive(Diagnostic)]
+#[diag(driver_ice_bug_report)]
+pub(crate) struct IceBugReport<'a> {
+    pub bug_report_url: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(driver_ice_version)]
+pub(crate) struct IceVersion<'a> {
+    pub version: &'a str,
+    pub triple: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(driver_ice_flags)]
+pub(crate) struct IceFlags {
+    pub flags: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(driver_ice_exclude_cargo_defaults)]
+pub(crate) struct IceExcludeCargoDefaults;

compiler/rustc_error_codes/src/error_codes.rs

@@ -5,7 +5,7 @@
 // /!\ IMPORTANT /!\
 //
 // Error messages' format must follow the RFC 1567 available here:
-// https://github.com/rust-lang/rfcs/pull/1567
+// https://rust-lang.github.io/rfcs/1567-long-error-codes-explanation-normalization.html
 
 register_diagnostics! {
 E0001: include_str!("./error_codes/E0001.md"),
@@ -510,6 +510,7 @@ E0789: include_str!("./error_codes/E0789.md"),
 E0790: include_str!("./error_codes/E0790.md"),
 E0791: include_str!("./error_codes/E0791.md"),
 E0792: include_str!("./error_codes/E0792.md"),
+E0793: include_str!("./error_codes/E0793.md"),
 ;
 //  E0006, // merged with E0005
 //  E0008, // cannot bind by-move into a pattern guard

compiler/rustc_error_codes/src/error_codes/E0793.md

@@ -0,0 +1,64 @@
+An unaligned references to a field of a [packed] struct got created.
+
+Erroneous code example:
+
+```compile_fail,E0793
+#[repr(packed)]
+pub struct Foo {
+    field1: u64,
+    field2: u8,
+}
+
+unsafe {
+    let foo = Foo { field1: 0, field2: 0 };
+    // Accessing the field directly is fine.
+    let val = foo.field1;
+    // A reference to a packed field causes a error.
+    let val = &foo.field1; // ERROR
+    // An implicit `&` is added in format strings, causing the same error.
+    println!("{}", foo.field1); // ERROR
+}
+```
+
+Creating a reference to an insufficiently aligned packed field is
+[undefined behavior] and therefore disallowed. Using an `unsafe` block does not
+change anything about this. Instead, the code should do a copy of the data in
+the packed field or use raw pointers and unaligned accesses.
+
+```
+#[repr(packed)]
+pub struct Foo {
+    field1: u64,
+    field2: u8,
+}
+
+unsafe {
+    let foo = Foo { field1: 0, field2: 0 };
+
+    // Instead of a reference, we can create a raw pointer...
+    let ptr = std::ptr::addr_of!(foo.field1);
+    // ... and then (crucially!) access it in an explicitly unaligned way.
+    let val = unsafe { ptr.read_unaligned() };
+    // This would *NOT* be correct:
+    // let val = unsafe { *ptr }; // Undefined Behavior due to unaligned load!
+
+    // For formatting, we can create a copy to avoid the direct reference.
+    let copy = foo.field1;
+    println!("{}", copy);
+    // Creating a copy can be written in a single line with curly braces.
+    // (This is equivalent to the two lines above.)
+    println!("{}", { foo.field1 });
+}
+```
+
+### Additional information
+
+Note that this error is specifically about *references* to packed fields.
+Direct by-value access of those fields is fine, since then the compiler has
+enough information to generate the correct kind of access.
+
+See [issue #82523] for more information.
+
+[packed]: https://doc.rust-lang.org/reference/type-layout.html#the-alignment-modifiers
+[undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
+[issue #82523]: https://github.com/rust-lang/rust/issues/82523

compiler/rustc_error_messages/locales/en-US/codegen_llvm.ftl

@@ -39,5 +39,51 @@ codegen_llvm_dynamic_linking_with_lto =
     cannot prefer dynamic linking when performing LTO
     .note = only 'staticlib', 'bin', and 'cdylib' outputs are supported with LTO
 
-codegen_llvm_fail_parsing_target_machine_config_to_target_machine =
+codegen_llvm_parse_target_machine_config =
     failed to parse target machine config to target machine: {$error}
+
+codegen_llvm_lto_disallowed = lto can only be run for executables, cdylibs and static library outputs
+
+codegen_llvm_lto_dylib = lto cannot be used for `dylib` crate type without `-Zdylib-lto`
+
+codegen_llvm_lto_bitcode_from_rlib = failed to get bitcode from object file for LTO ({$llvm_err})
+
+codegen_llvm_write_output = could not write output to {$path}
+codegen_llvm_write_output_with_llvm_err = could not write output to {$path}: {$llvm_err}
+
+codegen_llvm_target_machine = could not create LLVM TargetMachine for triple: {$triple}
+codegen_llvm_target_machine_with_llvm_err = could not create LLVM TargetMachine for triple: {$triple}: {$llvm_err}
+
+codegen_llvm_run_passes = failed to run LLVM passes
+codegen_llvm_run_passes_with_llvm_err = failed to run LLVM passes: {$llvm_err}
+
+codegen_llvm_serialize_module = failed to serialize module {$name}
+codegen_llvm_serialize_module_with_llvm_err = failed to serialize module {$name}: {$llvm_err}
+
+codegen_llvm_write_ir = failed to write LLVM IR to {$path}
+codegen_llvm_write_ir_with_llvm_err = failed to write LLVM IR to {$path}: {$llvm_err}
+
+codegen_llvm_prepare_thin_lto_context = failed to prepare thin LTO context
+codegen_llvm_prepare_thin_lto_context_with_llvm_err = failed to prepare thin LTO context: {$llvm_err}
+
+codegen_llvm_load_bitcode = failed to load bitcode of module "{$name}"
+codegen_llvm_load_bitcode_with_llvm_err = failed to load bitcode of module "{$name}": {$llvm_err}
+
+codegen_llvm_write_thinlto_key = error while writing ThinLTO key data: {$err}
+codegen_llvm_write_thinlto_key_with_llvm_err = error while writing ThinLTO key data: {$err}: {$llvm_err}
+
+codegen_llvm_multiple_source_dicompileunit = multiple source DICompileUnits found
+codegen_llvm_multiple_source_dicompileunit_with_llvm_err = multiple source DICompileUnits found: {$llvm_err}
+
+codegen_llvm_prepare_thin_lto_module = failed to prepare thin LTO module
+codegen_llvm_prepare_thin_lto_module_with_llvm_err = failed to prepare thin LTO module: {$llvm_err}
+
+codegen_llvm_parse_bitcode = failed to parse bitcode for LTO module
+codegen_llvm_parse_bitcode_with_llvm_err = failed to parse bitcode for LTO module: {$llvm_err}
+
+codegen_llvm_from_llvm_optimization_diag = {$filename}:{$line}:{$column} {$pass_name}: {$message}
+codegen_llvm_from_llvm_diag = {$message}
+
+codegen_llvm_write_bytecode = failed to write bytecode to {$path}: {$err}
+
+codegen_llvm_copy_bitcode = failed to copy bitcode to object file: {$err}

compiler/rustc_error_messages/locales/en-US/driver.ftl

@@ -11,3 +11,9 @@ driver_rlink_rustc_version_mismatch = .rlink file was produced by rustc version
 driver_rlink_no_a_file = rlink must be a file
 
 driver_unpretty_dump_fail = pretty-print failed to write `{$path}` due to error `{$err}`
+
+driver_ice = the compiler unexpectedly panicked. this is a bug.
+driver_ice_bug_report = we would appreciate a bug report: {$bug_report_url}
+driver_ice_version = rustc {$version} running on {$triple}
+driver_ice_flags = compiler flags: {$flags}
+driver_ice_exclude_cargo_defaults = some of the compiler flags provided by cargo are hidden

compiler/rustc_error_messages/locales/en-US/expand.ftl

@@ -127,3 +127,5 @@ expand_module_file_not_found =
 expand_module_multiple_candidates =
     file for module `{$name}` found at both "{$default_path}" and "{$secondary_path}"
     .help = delete or rename one of them to remove the ambiguity
+
+expand_trace_macro = trace_macro

compiler/rustc_error_messages/locales/en-US/incremental.ftl

@@ -0,0 +1,118 @@
+incremental_unrecognized_depnode = unrecognized `DepNode` variant: {$name}
+
+incremental_missing_depnode = missing `DepNode` variant
+
+incremental_missing_if_this_changed = no `#[rustc_if_this_changed]` annotation detected
+
+incremental_no_path = no path from `{$source}` to `{$target}`
+
+incremental_ok = OK
+
+incremental_unknown_reuse_kind = unknown cgu-reuse-kind `{$kind}` specified
+
+incremental_missing_query_depgraph =
+    found CGU-reuse attribute but `-Zquery-dep-graph` was not specified
+
+incremental_malformed_cgu_name =
+    found malformed codegen unit name `{$user_path}`. codegen units names must always start with the name of the crate (`{$crate_name}` in this case).
+
+incremental_no_module_named =
+    no module named `{$user_path}` (mangled: {$cgu_name}). available modules: {$cgu_names}
+
+incremental_field_associated_value_expected = associated value expected for `{$name}`
+
+incremental_no_field = no field `{$name}`
+
+incremental_assertion_auto =
+    `except` specified DepNodes that can not be affected for \"{$name}\": \"{$e}\"
+
+incremental_undefined_clean_dirty_assertions_item =
+    clean/dirty auto-assertions not yet defined for Node::Item.node={$kind}
+
+incremental_undefined_clean_dirty_assertions =
+    clean/dirty auto-assertions not yet defined for {$kind}
+
+incremental_repeated_depnode_label = dep-node label `{$label}` is repeated
+
+incremental_unrecognized_depnode_label = dep-node label `{$label}` not recognized
+
+incremental_not_dirty = `{$dep_node_str}` should be dirty but is not
+
+incremental_not_clean = `{$dep_node_str}` should be clean but is not
+
+incremental_not_loaded = `{$dep_node_str}` should have been loaded from disk but it was not
+
+incremental_unknown_item = unknown item `{$name}`
+
+incremental_no_cfg = no cfg attribute
+
+incremental_associated_value_expected_for = associated value expected for `{$ident}`
+
+incremental_associated_value_expected = expected an associated value
+
+incremental_unchecked_clean = found unchecked `#[rustc_clean]` attribute
+
+incremental_delete_old = unable to delete old {$name} at `{$path}`: {$err}
+
+incremental_create_new = failed to create {$name} at `{$path}`: {$err}
+
+incremental_write_new = failed to write {$name} to `{$path}`: {$err}
+
+incremental_canonicalize_path = incremental compilation: error canonicalizing path `{$path}`: {$err}
+
+incremental_create_incr_comp_dir =
+    could not create incremental compilation {$tag} directory `{$path}`: {$err}
+
+incremental_create_lock =
+    incremental compilation: could not create session directory lock file: {$lock_err}
+incremental_lock_unsupported =
+    the filesystem for the incremental path at {$session_dir} does not appear to support locking, consider changing the incremental path to a filesystem that supports locking or disable incremental compilation
+incremental_cargo_help_1 =
+    incremental compilation can be disabled by setting the environment variable CARGO_INCREMENTAL=0 (see https://doc.rust-lang.org/cargo/reference/profiles.html#incremental)
+incremental_cargo_help_2 =
+    the entire build directory can be changed to a different filesystem by setting the environment variable CARGO_TARGET_DIR to a different path (see https://doc.rust-lang.org/cargo/reference/config.html#buildtarget-dir)
+
+incremental_delete_lock =
+    error deleting lock file for incremental compilation session directory `{$path}`: {$err}
+
+incremental_hard_link_failed =
+    hard linking files in the incremental compilation cache failed. copying files instead. consider moving the cache directory to a file system which supports hard linking in session dir `{$path}`
+
+incremental_delete_partial = failed to delete partly initialized session dir `{$path}`: {$err}
+
+incremental_delete_full = error deleting incremental compilation session directory `{$path}`: {$err}
+
+incremental_finalize = error finalizing incremental compilation session directory `{$path}`: {$err}
+
+incremental_invalid_gc_failed =
+    failed to garbage collect invalid incremental compilation session directory `{$path}`: {$err}
+
+incremental_finalized_gc_failed =
+    failed to garbage collect finalized incremental compilation session directory `{$path}`: {$err}
+
+incremental_session_gc_failed =
+    failed to garbage collect incremental compilation session directory `{$path}`: {$err}
+
+incremental_assert_not_loaded =
+    we asserted that the incremental cache should not be loaded, but it was loaded
+
+incremental_assert_loaded =
+    we asserted that an existing incremental cache directory should be successfully loaded, but it was not
+
+incremental_delete_incompatible =
+    failed to delete invalidated or incompatible incremental compilation session directory contents `{$path}`: {$err}
+
+incremental_load_dep_graph = could not load dep-graph from `{$path}`: {$err}
+
+incremental_decode_incr_cache = could not decode incremental cache: {$err}
+
+incremental_write_dep_graph = failed to write dependency graph to `{$path}`: {$err}
+
+incremental_move_dep_graph = failed to move dependency graph from `{$from}` to `{$to}`: {$err}
+
+incremental_create_dep_graph = failed to create dependency graph at `{$path}`: {$err}
+
+incremental_copy_workproduct_to_cache =
+    error copying object file `{$from}` to incremental directory as `{$to}`: {$err}
+
+incremental_delete_workproduct = file-system error deleting outdated file `{$path}`: {$err}

compiler/rustc_error_messages/locales/en-US/interface.ftl

@@ -44,3 +44,13 @@ interface_failed_writing_file =
 
 interface_proc_macro_crate_panic_abort =
     building proc macro crate with `panic=abort` may crash the compiler should the proc-macro panic
+
+interface_unsupported_crate_type_for_target =
+    dropping unsupported crate type `{$crate_type}` for target `{$target_triple}`
+
+interface_multiple_output_types_adaption =
+    due to multiple output types requested, the explicitly specified output file name will be adapted for each output type
+
+interface_ignoring_extra_filename = ignoring -C extra-filename flag due to -o flag
+
+interface_ignoring_out_dir = ignoring --out-dir flag due to -o flag

compiler/rustc_error_messages/locales/en-US/monomorphize.ftl

@@ -24,3 +24,9 @@ monomorphize_large_assignments =
 
 monomorphize_couldnt_dump_mono_stats =
     unexpected error occurred while dumping monomorphization stats: {$error}
+
+monomorphize_encountered_error_while_instantiating =
+    the above error was encountered while instantiating `{$formatted_item}`
+
+monomorphize_unknown_cgu_collection_mode =
+    unknown codegen-item collection mode '{$mode}', falling back to 'lazy' mode

compiler/rustc_error_messages/locales/en-US/passes.ftl

@@ -731,3 +731,5 @@ passes_proc_macro_missing_args = mismatched {$kind} signature
 passes_proc_macro_invalid_abi = proc macro functions may not be `extern "{$abi}"`
 
 passes_proc_macro_unsafe = proc macro functions may not be `unsafe`
+
+passes_skipping_const_checks = skipping const checks

compiler/rustc_error_messages/locales/en-US/session.ftl

@@ -89,3 +89,5 @@ session_int_literal_too_large = integer literal is too large
 
 session_invalid_int_literal_width = invalid width `{$width}` for integer literal
     .help = valid widths are 8, 16, 32, 64 and 128
+
+session_optimization_fuel_exhausted = optimization-fuel-exhausted: {$msg}

compiler/rustc_error_messages/src/lib.rs

@@ -52,6 +52,7 @@ fluent_messages! {
     expand => "../locales/en-US/expand.ftl",
     hir_analysis => "../locales/en-US/hir_analysis.ftl",
     hir_typeck => "../locales/en-US/hir_typeck.ftl",
+    incremental => "../locales/en-US/incremental.ftl",
     infer => "../locales/en-US/infer.ftl",
     interface => "../locales/en-US/interface.ftl",
     lint => "../locales/en-US/lint.ftl",

compiler/rustc_errors/src/diagnostic.rs

@@ -1051,6 +1051,7 @@ impl Diagnostic {
     ) -> (
         &Level,
         &[(DiagnosticMessage, Style)],
+        Vec<(&Cow<'static, str>, &DiagnosticArgValue<'static>)>,
         &Option<DiagnosticId>,
         &MultiSpan,
         &Result<Vec<CodeSuggestion>, SuggestionsDisabled>,
@@ -1059,6 +1060,7 @@ impl Diagnostic {
         (
             &self.level,
             &self.message,
+            self.args().collect(),
             &self.code,
             &self.span,
             &self.suggestions,

compiler/rustc_errors/src/diagnostic_builder.rs

@@ -408,6 +408,59 @@ impl EmissionGuarantee for ! {
     }
 }
 
+impl<'a> DiagnosticBuilder<'a, rustc_span::fatal_error::FatalError> {
+    /// Convenience function for internal use, clients should use one of the
+    /// `struct_*` methods on [`Handler`].
+    #[track_caller]
+    pub(crate) fn new_almost_fatal(
+        handler: &'a Handler,
+        message: impl Into<DiagnosticMessage>,
+    ) -> Self {
+        let diagnostic = Diagnostic::new_with_code(Level::Fatal, None, message);
+        Self::new_diagnostic_almost_fatal(handler, diagnostic)
+    }
+
+    /// Creates a new `DiagnosticBuilder` with an already constructed
+    /// diagnostic.
+    pub(crate) fn new_diagnostic_almost_fatal(
+        handler: &'a Handler,
+        diagnostic: Diagnostic,
+    ) -> Self {
+        debug!("Created new diagnostic");
+        Self {
+            inner: DiagnosticBuilderInner {
+                state: DiagnosticBuilderState::Emittable(handler),
+                diagnostic: Box::new(diagnostic),
+            },
+            _marker: PhantomData,
+        }
+    }
+}
+
+impl EmissionGuarantee for rustc_span::fatal_error::FatalError {
+    fn diagnostic_builder_emit_producing_guarantee(db: &mut DiagnosticBuilder<'_, Self>) -> Self {
+        match db.inner.state {
+            // First `.emit()` call, the `&Handler` is still available.
+            DiagnosticBuilderState::Emittable(handler) => {
+                db.inner.state = DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation;
+
+                handler.emit_diagnostic(&mut db.inner.diagnostic);
+            }
+            // `.emit()` was previously called, disallowed from repeating it.
+            DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation => {}
+        }
+        // Then fatally error..
+        rustc_span::fatal_error::FatalError
+    }
+
+    fn make_diagnostic_builder(
+        handler: &Handler,
+        msg: impl Into<DiagnosticMessage>,
+    ) -> DiagnosticBuilder<'_, Self> {
+        DiagnosticBuilder::new_almost_fatal(handler, msg)
+    }
+}
+
 /// In general, the `DiagnosticBuilder` uses deref to allow access to
 /// the fields and methods of the embedded `diagnostic` in a
 /// transparent way. *However,* many of the methods are intended to

compiler/rustc_errors/src/diagnostic_impls.rs

@@ -36,6 +36,12 @@ impl<'a, T: fmt::Display> From<&'a T> for DiagnosticArgFromDisplay<'a> {
     }
 }
 
+impl<'a, T: Clone + IntoDiagnosticArg> IntoDiagnosticArg for &'a T {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        self.clone().into_diagnostic_arg()
+    }
+}
+
 macro_rules! into_diagnostic_arg_using_display {
     ($( $ty:ty ),+ $(,)?) => {
         $(
@@ -153,12 +159,6 @@ impl IntoDiagnosticArg for ast::Path {
     }
 }
 
-impl IntoDiagnosticArg for &ast::Path {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(pprust::path_to_string(self)))
-    }
-}
-
 impl IntoDiagnosticArg for ast::token::Token {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
         DiagnosticArgValue::Str(pprust::token_to_string(&self))
@@ -177,6 +177,18 @@ impl IntoDiagnosticArg for type_ir::FloatTy {
     }
 }
 
+impl IntoDiagnosticArg for std::ffi::CString {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.to_string_lossy().into_owned()))
+    }
+}
+
+impl IntoDiagnosticArg for rustc_data_structures::small_c_str::SmallCStr {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.to_string_lossy().into_owned()))
+    }
+}
+
 impl IntoDiagnosticArg for Level {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
         DiagnosticArgValue::Str(Cow::Borrowed(self.to_cmd_flag()))

compiler/rustc_errors/src/emitter.rs

@@ -2113,30 +2113,38 @@ impl EmitterWriter {
                         }
                     }
                     for sugg in suggestions {
-                        if sugg.style == SuggestionStyle::CompletelyHidden {
-                            // do not display this suggestion, it is meant only for tools
-                        } else if sugg.style == SuggestionStyle::HideCodeAlways {
-                            if let Err(e) = self.emit_message_default(
-                                &MultiSpan::new(),
-                                &[(sugg.msg.to_owned(), Style::HeaderMsg)],
-                                args,
-                                &None,
-                                &Level::Help,
-                                max_line_num_len,
-                                true,
-                                None,
-                            ) {
-                                panic!("failed to emit error: {}", e);
+                        match sugg.style {
+                            SuggestionStyle::CompletelyHidden => {
+                                // do not display this suggestion, it is meant only for tools
                             }
-                        } else if let Err(e) = self.emit_suggestion_default(
-                            span,
-                            sugg,
-                            args,
-                            &Level::Help,
-                            max_line_num_len,
-                        ) {
-                            panic!("failed to emit error: {}", e);
-                        };
+                            SuggestionStyle::HideCodeAlways => {
+                                if let Err(e) = self.emit_message_default(
+                                    &MultiSpan::new(),
+                                    &[(sugg.msg.to_owned(), Style::HeaderMsg)],
+                                    args,
+                                    &None,
+                                    &Level::Help,
+                                    max_line_num_len,
+                                    true,
+                                    None,
+                                ) {
+                                    panic!("failed to emit error: {}", e);
+                                }
+                            }
+                            SuggestionStyle::HideCodeInline
+                            | SuggestionStyle::ShowCode
+                            | SuggestionStyle::ShowAlways => {
+                                if let Err(e) = self.emit_suggestion_default(
+                                    span,
+                                    sugg,
+                                    args,
+                                    &Level::Help,
+                                    max_line_num_len,
+                                ) {
+                                    panic!("failed to emit error: {}", e);
+                                }
+                            }
+                        }
                     }
                 }
             }

compiler/rustc_errors/src/lib.rs

@@ -617,22 +617,24 @@ impl Handler {
         }
     }
 
-    /// Translate `message` eagerly with `args`.
+    /// Translate `message` eagerly with `args` to `SubdiagnosticMessage::Eager`.
     pub fn eagerly_translate<'a>(
         &self,
         message: DiagnosticMessage,
         args: impl Iterator<Item = DiagnosticArg<'a, 'static>>,
     ) -> SubdiagnosticMessage {
+        SubdiagnosticMessage::Eager(self.eagerly_translate_to_string(message, args))
+    }
+
+    /// Translate `message` eagerly with `args` to `String`.
+    pub fn eagerly_translate_to_string<'a>(
+        &self,
+        message: DiagnosticMessage,
+        args: impl Iterator<Item = DiagnosticArg<'a, 'static>>,
+    ) -> String {
         let inner = self.inner.borrow();
         let args = crate::translation::to_fluent_args(args);
-        SubdiagnosticMessage::Eager(
-            inner
-                .emitter
-                .translate_message(&message, &args)
-                .map_err(Report::new)
-                .unwrap()
-                .to_string(),
-        )
+        inner.emitter.translate_message(&message, &args).map_err(Report::new).unwrap().to_string()
     }
 
     // This is here to not allow mutation of flags;
@@ -1010,6 +1012,7 @@ impl Handler {
     }
 
     #[track_caller]
+    #[rustc_lint_diagnostics]
     pub fn span_note_without_error(
         &self,
         span: impl Into<MultiSpan>,
@@ -1019,6 +1022,7 @@ impl Handler {
     }
 
     #[track_caller]
+    #[rustc_lint_diagnostics]
     pub fn span_note_diag(
         &self,
         span: Span,
@@ -1030,19 +1034,23 @@ impl Handler {
     }
 
     // NOTE: intentionally doesn't raise an error so rustc_codegen_ssa only reports fatal errors in the main thread
+    #[rustc_lint_diagnostics]
     pub fn fatal(&self, msg: impl Into<DiagnosticMessage>) -> FatalError {
         self.inner.borrow_mut().fatal(msg)
     }
 
+    #[rustc_lint_diagnostics]
     pub fn err(&self, msg: impl Into<DiagnosticMessage>) -> ErrorGuaranteed {
         self.inner.borrow_mut().err(msg)
     }
 
+    #[rustc_lint_diagnostics]
     pub fn warn(&self, msg: impl Into<DiagnosticMessage>) {
         let mut db = DiagnosticBuilder::new(self, Warning(None), msg);
         db.emit();
     }
 
+    #[rustc_lint_diagnostics]
     pub fn note_without_error(&self, msg: impl Into<DiagnosticMessage>) {
         DiagnosticBuilder::new(self, Note, msg).emit();
     }
@@ -1059,6 +1067,7 @@ impl Handler {
     pub fn has_errors(&self) -> Option<ErrorGuaranteed> {
         if self.inner.borrow().has_errors() { Some(ErrorGuaranteed(())) } else { None }
     }
+
     pub fn has_errors_or_lint_errors(&self) -> Option<ErrorGuaranteed> {
         if self.inner.borrow().has_errors_or_lint_errors() {
             Some(ErrorGuaranteed::unchecked_claim_error_was_emitted())
@@ -1132,6 +1141,20 @@ impl Handler {
         self.create_warning(warning).emit()
     }
 
+    pub fn create_almost_fatal<'a>(
+        &'a self,
+        fatal: impl IntoDiagnostic<'a, FatalError>,
+    ) -> DiagnosticBuilder<'a, FatalError> {
+        fatal.into_diagnostic(self)
+    }
+
+    pub fn emit_almost_fatal<'a>(
+        &'a self,
+        fatal: impl IntoDiagnostic<'a, FatalError>,
+    ) -> FatalError {
+        self.create_almost_fatal(fatal).emit()
+    }
+
     pub fn create_fatal<'a>(
         &'a self,
         fatal: impl IntoDiagnostic<'a, !>,
@@ -1157,6 +1180,17 @@ impl Handler {
         self.create_bug(bug).emit()
     }
 
+    pub fn emit_note<'a>(&'a self, note: impl IntoDiagnostic<'a, Noted>) -> Noted {
+        self.create_note(note).emit()
+    }
+
+    pub fn create_note<'a>(
+        &'a self,
+        note: impl IntoDiagnostic<'a, Noted>,
+    ) -> DiagnosticBuilder<'a, Noted> {
+        note.into_diagnostic(self)
+    }
+
     fn emit_diag_at_span(
         &self,
         mut diag: Diagnostic,

compiler/rustc_errors/src/styled_buffer.rs

@@ -142,7 +142,7 @@ impl StyledBuffer {
     pub fn set_style(&mut self, line: usize, col: usize, style: Style, overwrite: bool) {
         if let Some(ref mut line) = self.lines.get_mut(line) {
             if let Some(StyledChar { style: s, .. }) = line.get_mut(col) {
-                if overwrite || *s == Style::NoStyle || *s == Style::Quotation {
+                if overwrite || matches!(s, Style::NoStyle | Style::Quotation) {
                     *s = style;
                 }
             }

compiler/rustc_expand/src/base.rs

@@ -4,7 +4,7 @@ use crate::errors::{
     ArgumentNotAttributes, AttrNoArguments, AttributeMetaItem, AttributeSingleWord,
     AttributesWrongForm, CannotBeNameOfMacro, ExpectedCommaInList, HelperAttributeNameInvalid,
     MacroBodyStability, MacroConstStability, NotAMetaItem, OnlyOneArgument, OnlyOneWord,
-    ResolveRelativePath, TakesNoArguments,
+    ResolveRelativePath, TakesNoArguments, TraceMacro,
 };
 use crate::expand::{self, AstFragment, Invocation};
 use crate::module::DirOwnership;
@@ -1142,8 +1142,8 @@ impl<'a> ExtCtxt<'a> {
         self.sess.parse_sess.span_diagnostic.span_bug(sp, msg);
     }
     pub fn trace_macros_diag(&mut self) {
-        for (sp, notes) in self.expansions.iter() {
-            let mut db = self.sess.parse_sess.span_diagnostic.span_note_diag(*sp, "trace_macro");
+        for (span, notes) in self.expansions.iter() {
+            let mut db = self.sess.parse_sess.create_note(TraceMacro { span: *span });
             for note in notes {
                 db.note(note);
             }

compiler/rustc_expand/src/errors.rs

@@ -368,3 +368,10 @@ pub(crate) struct ModuleMultipleCandidates {
     pub default_path: String,
     pub secondary_path: String,
 }
+
+#[derive(Diagnostic)]
+#[diag(expand_trace_macro)]
+pub struct TraceMacro {
+    #[primary_span]
+    pub span: Span,
+}

compiler/rustc_expand/src/mbe/macro_parser.rs

@@ -503,7 +503,7 @@ impl TtParser {
                         mp.push_match(metavar_idx, seq_depth, MatchedSeq(vec![]));
                     }
 
-                    if op == KleeneOp::ZeroOrMore || op == KleeneOp::ZeroOrOne {
+                    if matches!(op, KleeneOp::ZeroOrMore | KleeneOp::ZeroOrOne) {
                         // Try zero matches of this sequence, by skipping over it.
                         self.cur_mps.push(MatcherPos {
                             idx: idx_first_after,

compiler/rustc_feature/src/accepted.rs

@@ -49,7 +49,7 @@ declare_features! (
     /// Allows `#[target_feature(...)]` on aarch64 platforms
     (accepted, aarch64_target_feature, "1.61.0", Some(44839), None),
     /// Allows using the `efiapi` ABI.
-    (accepted, abi_efiapi, "CURRENT_RUSTC_VERSION", Some(65815), None),
+    (accepted, abi_efiapi, "1.68.0", Some(65815), None),
     /// Allows the sysV64 ABI to be specified on all platforms
     /// instead of just the platforms on which it is the C ABI.
     (accepted, abi_sysv64, "1.24.0", Some(36167), None),
@@ -129,7 +129,7 @@ declare_features! (
     /// Allows `crate` in paths.
     (accepted, crate_in_paths, "1.30.0", Some(45477), None),
     /// Allows rustc to inject a default alloc_error_handler
-    (accepted, default_alloc_error_handler, "CURRENT_RUSTC_VERSION", Some(66741), None),
+    (accepted, default_alloc_error_handler, "1.68.0", Some(66741), None),
     /// Allows using assigning a default type to type parameters in algebraic data type definitions.
     (accepted, default_type_params, "1.0.0", None, None),
     /// Allows `#[deprecated]` attribute.
@@ -164,7 +164,7 @@ declare_features! (
     /// Allows access to crate names passed via `--extern` through prelude.
     (accepted, extern_prelude, "1.30.0", Some(44660), None),
     /// Allows using F16C intrinsics from `core::arch::{x86, x86_64}`.
-    (accepted, f16c_target_feature, "CURRENT_RUSTC_VERSION", Some(44839), None),
+    (accepted, f16c_target_feature, "1.68.0", Some(44839), None),
     /// Allows field shorthands (`x` meaning `x: x`) in struct literal expressions.
     (accepted, field_init_shorthand, "1.17.0", Some(37340), None),
     /// Allows `#[must_use]` on functions, and introduces must-use operators (RFC 1940).

compiler/rustc_feature/src/active.rs

@@ -342,7 +342,7 @@ declare_features! (
     /// Allows `async {}` expressions in const contexts.
     (active, const_async_blocks, "1.53.0", Some(85368), None),
     /// Allows `const || {}` closures in const contexts.
-    (incomplete, const_closures, "CURRENT_RUSTC_VERSION", Some(106003), None),
+    (incomplete, const_closures, "1.68.0", Some(106003), None),
     /// Allows limiting the evaluation steps of const expressions
     (active, const_eval_limit, "1.43.0", Some(67217), None),
     /// Allows the definition of `const extern fn` and `const unsafe extern fn`.

compiler/rustc_hir_analysis/src/astconv/generics.rs

@@ -385,10 +385,9 @@ pub fn check_generic_arg_count_for_call(
 ) -> GenericArgCountResult {
     let empty_args = hir::GenericArgs::none();
     let gen_args = seg.args.unwrap_or(&empty_args);
-    let gen_pos = if is_method_call == IsMethodCall::Yes {
-        GenericArgPosition::MethodCall
-    } else {
-        GenericArgPosition::Value
+    let gen_pos = match is_method_call {
+        IsMethodCall::Yes => GenericArgPosition::MethodCall,
+        IsMethodCall::No => GenericArgPosition::Value,
     };
     let has_self = generics.parent.is_none() && generics.has_self;
 

compiler/rustc_hir_analysis/src/check/check.rs

@@ -442,6 +442,7 @@ fn check_opaque_meets_bounds<'tcx>(
     match ocx.eq(&misc_cause, param_env, opaque_ty, hidden_ty) {
         Ok(()) => {}
         Err(ty_err) => {
+            let ty_err = ty_err.to_string(tcx);
             tcx.sess.delay_span_bug(
                 span,
                 &format!("could not unify `{hidden_ty}` with revealed type:\n{ty_err}"),
@@ -605,59 +606,66 @@ fn check_item_type(tcx: TyCtxt<'_>, id: hir::ItemId) {
             };
             check_abi(tcx, it.hir_id(), it.span, abi);
 
-            if abi == Abi::RustIntrinsic {
-                for item in items {
-                    let item = tcx.hir().foreign_item(item.id);
-                    intrinsic::check_intrinsic_type(tcx, item);
-                }
-            } else if abi == Abi::PlatformIntrinsic {
-                for item in items {
-                    let item = tcx.hir().foreign_item(item.id);
-                    intrinsic::check_platform_intrinsic_type(tcx, item);
-                }
-            } else {
-                for item in items {
-                    let def_id = item.id.owner_id.def_id;
-                    let generics = tcx.generics_of(def_id);
-                    let own_counts = generics.own_counts();
-                    if generics.params.len() - own_counts.lifetimes != 0 {
-                        let (kinds, kinds_pl, egs) = match (own_counts.types, own_counts.consts) {
-                            (_, 0) => ("type", "types", Some("u32")),
-                            // We don't specify an example value, because we can't generate
-                            // a valid value for any type.
-                            (0, _) => ("const", "consts", None),
-                            _ => ("type or const", "types or consts", None),
-                        };
-                        struct_span_err!(
-                            tcx.sess,
-                            item.span,
-                            E0044,
-                            "foreign items may not have {kinds} parameters",
-                        )
-                        .span_label(item.span, &format!("can't have {kinds} parameters"))
-                        .help(
-                            // FIXME: once we start storing spans for type arguments, turn this
-                            // into a suggestion.
-                            &format!(
-                                "replace the {} parameters with concrete {}{}",
-                                kinds,
-                                kinds_pl,
-                                egs.map(|egs| format!(" like `{}`", egs)).unwrap_or_default(),
-                            ),
-                        )
-                        .emit();
+            match abi {
+                Abi::RustIntrinsic => {
+                    for item in items {
+                        let item = tcx.hir().foreign_item(item.id);
+                        intrinsic::check_intrinsic_type(tcx, item);
                     }
+                }
 
-                    let item = tcx.hir().foreign_item(item.id);
-                    match &item.kind {
-                        hir::ForeignItemKind::Fn(fn_decl, _, _) => {
-                            require_c_abi_if_c_variadic(tcx, fn_decl, abi, item.span);
+                Abi::PlatformIntrinsic => {
+                    for item in items {
+                        let item = tcx.hir().foreign_item(item.id);
+                        intrinsic::check_platform_intrinsic_type(tcx, item);
+                    }
+                }
+
+                _ => {
+                    for item in items {
+                        let def_id = item.id.owner_id.def_id;
+                        let generics = tcx.generics_of(def_id);
+                        let own_counts = generics.own_counts();
+                        if generics.params.len() - own_counts.lifetimes != 0 {
+                            let (kinds, kinds_pl, egs) = match (own_counts.types, own_counts.consts)
+                            {
+                                (_, 0) => ("type", "types", Some("u32")),
+                                // We don't specify an example value, because we can't generate
+                                // a valid value for any type.
+                                (0, _) => ("const", "consts", None),
+                                _ => ("type or const", "types or consts", None),
+                            };
+                            struct_span_err!(
+                                tcx.sess,
+                                item.span,
+                                E0044,
+                                "foreign items may not have {kinds} parameters",
+                            )
+                            .span_label(item.span, &format!("can't have {kinds} parameters"))
+                            .help(
+                                // FIXME: once we start storing spans for type arguments, turn this
+                                // into a suggestion.
+                                &format!(
+                                    "replace the {} parameters with concrete {}{}",
+                                    kinds,
+                                    kinds_pl,
+                                    egs.map(|egs| format!(" like `{}`", egs)).unwrap_or_default(),
+                                ),
+                            )
+                            .emit();
                         }
-                        hir::ForeignItemKind::Static(..) => {
-                            check_static_inhabited(tcx, def_id);
-                            check_static_linkage(tcx, def_id);
+
+                        let item = tcx.hir().foreign_item(item.id);
+                        match &item.kind {
+                            hir::ForeignItemKind::Fn(fn_decl, _, _) => {
+                                require_c_abi_if_c_variadic(tcx, fn_decl, abi, item.span);
+                            }
+                            hir::ForeignItemKind::Static(..) => {
+                                check_static_inhabited(tcx, def_id);
+                                check_static_linkage(tcx, def_id);
+                            }
+                            _ => {}
                         }
-                        _ => {}
                     }
                 }
             }

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -1930,7 +1930,7 @@ pub(super) fn check_type_bounds<'tcx>(
         smallvec::SmallVec::with_capacity(defs.count());
     InternalSubsts::fill_single(&mut substs, defs, &mut |param, _| match param.kind {
         GenericParamDefKind::Type { .. } => {
-            let kind = ty::BoundTyKind::Param(param.name);
+            let kind = ty::BoundTyKind::Param(param.def_id, param.name);
             let bound_var = ty::BoundVariableKind::Ty(kind);
             bound_vars.push(bound_var);
             tcx.mk_ty(ty::Bound(

compiler/rustc_hir_pretty/src/lib.rs

@@ -9,9 +9,7 @@ use rustc_ast_pretty::pp::{self, Breaks};
 use rustc_ast_pretty::pprust::{Comments, PrintState};
 use rustc_hir as hir;
 use rustc_hir::LifetimeParamKind;
-use rustc_hir::{
-    BindingAnnotation, ByRef, GenericArg, GenericParam, GenericParamKind, Mutability, Node, Term,
-};
+use rustc_hir::{BindingAnnotation, ByRef, GenericArg, GenericParam, GenericParamKind, Node, Term};
 use rustc_hir::{GenericBound, PatKind, RangeEnd, TraitBoundModifier};
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, Ident, IdentPrinter, Symbol};
@@ -1746,7 +1744,7 @@ impl<'a> State<'a> {
                 if by_ref == ByRef::Yes {
                     self.word_nbsp("ref");
                 }
-                if mutbl == Mutability::Mut {
+                if mutbl.is_mut() {
                     self.word_nbsp("mut");
                 }
                 self.print_ident(ident);

compiler/rustc_hir_typeck/src/closure.rs

@@ -15,6 +15,7 @@ use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{self, Ty, TypeSuperVisitable, TypeVisitor};
 use rustc_span::def_id::LocalDefId;
 use rustc_span::source_map::Span;
+use rustc_span::sym;
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::traits;
 use rustc_trait_selection::traits::error_reporting::ArgKind;
@@ -288,21 +289,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let trait_def_id = projection.trait_def_id(tcx);
 
         let is_fn = tcx.is_fn_trait(trait_def_id);
-        let gen_trait = tcx.require_lang_item(LangItem::Generator, cause_span);
-        let is_gen = gen_trait == trait_def_id;
+
+        let gen_trait = tcx.lang_items().gen_trait();
+        let is_gen = gen_trait == Some(trait_def_id);
+
         if !is_fn && !is_gen {
             debug!("not fn or generator");
             return None;
         }
 
-        if is_gen {
-            // Check that we deduce the signature from the `<_ as std::ops::Generator>::Return`
-            // associated item and not yield.
-            let return_assoc_item = self.tcx.associated_item_def_ids(gen_trait)[1];
-            if return_assoc_item != projection.projection_def_id() {
-                debug!("not return assoc item of generator");
-                return None;
-            }
+        // Check that we deduce the signature from the `<_ as std::ops::Generator>::Return`
+        // associated item and not yield.
+        if is_gen && self.tcx.associated_item(projection.projection_def_id()).name != sym::Return {
+            debug!("not `Return` assoc item of `Generator`");
+            return None;
         }
 
         let input_tys = if is_fn {

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -454,8 +454,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             None if let Some(e) = self.tainted_by_errors() => self.tcx.ty_error_with_guaranteed(e),
             None => {
                 bug!(
-                    "no type for node {}: {} in fcx {}",
-                    id,
+                    "no type for node {} in fcx {}",
                     self.tcx.hir().node_to_string(id),
                     self.tag()
                 );

compiler/rustc_hir_typeck/src/mem_categorization.rs

@@ -155,8 +155,7 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
             None if self.is_tainted_by_errors() => Err(()),
             None => {
                 bug!(
-                    "no type for node {}: {} in mem_categorization",
-                    id,
+                    "no type for node {} in mem_categorization",
                     self.tcx().hir().node_to_string(id)
                 );
             }

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -1354,13 +1354,12 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
             return Some(Err(MethodError::Ambiguity(sources)));
         }
 
-        applicable_candidates.pop().map(|(probe, status)| {
-            if status == ProbeResult::Match {
+        applicable_candidates.pop().map(|(probe, status)| match status {
+            ProbeResult::Match => {
                 Ok(probe
                     .to_unadjusted_pick(self_ty, unstable_candidates.cloned().unwrap_or_default()))
-            } else {
-                Err(MethodError::BadReturnType)
             }
+            ProbeResult::NoMatch | ProbeResult::BadReturnType => Err(MethodError::BadReturnType),
         })
     }
 }

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -259,7 +259,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let mode = no_match_data.mode;
         let tcx = self.tcx;
         let rcvr_ty = self.resolve_vars_if_possible(rcvr_ty);
-        let ty_str = with_forced_trimmed_paths!(self.ty_to_string(rcvr_ty));
+        let (ty_str, ty_file) = tcx.short_ty_string(rcvr_ty);
+        let short_ty_str = with_forced_trimmed_paths!(rcvr_ty.to_string());
         let is_method = mode == Mode::MethodCall;
         let unsatisfied_predicates = &no_match_data.unsatisfied_predicates;
         let similar_candidate = no_match_data.similar_candidate;
@@ -276,11 +277,24 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
         };
 
-        if self.suggest_wrapping_range_with_parens(tcx, rcvr_ty, source, span, item_name, &ty_str)
-            || self.suggest_constraining_numerical_ty(
-                tcx, rcvr_ty, source, span, item_kind, item_name, &ty_str,
-            )
-        {
+        // We could pass the file for long types into these two, but it isn't strictly necessary
+        // given how targetted they are.
+        if self.suggest_wrapping_range_with_parens(
+            tcx,
+            rcvr_ty,
+            source,
+            span,
+            item_name,
+            &short_ty_str,
+        ) || self.suggest_constraining_numerical_ty(
+            tcx,
+            rcvr_ty,
+            source,
+            span,
+            item_kind,
+            item_name,
+            &short_ty_str,
+        ) {
             return None;
         }
         span = item_name.span;
@@ -319,6 +333,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             rcvr_ty.prefix_string(self.tcx),
             ty_str_reported,
         );
+        let ty_str = if short_ty_str.len() < ty_str.len() && ty_str.len() > 10 {
+            short_ty_str
+        } else {
+            ty_str
+        };
+        if let Some(file) = ty_file {
+            err.note(&format!("the full type name has been written to '{}'", file.display(),));
+        }
         if rcvr_ty.references_error() {
             err.downgrade_to_delayed_bug();
         }
@@ -826,7 +848,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 let primary_message = primary_message.unwrap_or_else(|| {
                     format!(
                         "the {item_kind} `{item_name}` exists for {actual_prefix} `{ty_str}`, \
-                    but its trait bounds were not satisfied"
+                         but its trait bounds were not satisfied"
                     )
                 });
                 err.set_primary_message(&primary_message);

compiler/rustc_hir_typeck/src/op.rs

@@ -335,7 +335,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 format!("cannot divide `{lhs_ty}` by `{rhs_ty}`")
                             }
                             hir::BinOpKind::Rem => {
-                                format!("cannot mod `{lhs_ty}` by `{rhs_ty}`")
+                                format!(
+                                    "cannot calculate the remainder of `{lhs_ty}` divided by `{rhs_ty}`"
+                                )
                             }
                             hir::BinOpKind::BitAnd => {
                                 format!("no implementation for `{lhs_ty} & {rhs_ty}`")

compiler/rustc_incremental/src/assert_dep_graph.rs

@@ -33,6 +33,7 @@
 //! fn baz() { foo(); }
 //! ```
 
+use crate::errors;
 use rustc_ast as ast;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::graph::implementation::{Direction, NodeIndex, INCOMING, OUTGOING};
@@ -133,12 +134,10 @@ impl<'tcx> IfThisChanged<'tcx> {
                     Some(n) => {
                         match DepNode::from_label_string(self.tcx, n.as_str(), def_path_hash) {
                             Ok(n) => n,
-                            Err(()) => {
-                                self.tcx.sess.span_fatal(
-                                    attr.span,
-                                    &format!("unrecognized DepNode variant {:?}", n),
-                                );
-                            }
+                            Err(()) => self.tcx.sess.emit_fatal(errors::UnrecognizedDepNode {
+                                span: attr.span,
+                                name: n,
+                            }),
                         }
                     }
                 };
@@ -149,16 +148,14 @@ impl<'tcx> IfThisChanged<'tcx> {
                     Some(n) => {
                         match DepNode::from_label_string(self.tcx, n.as_str(), def_path_hash) {
                             Ok(n) => n,
-                            Err(()) => {
-                                self.tcx.sess.span_fatal(
-                                    attr.span,
-                                    &format!("unrecognized DepNode variant {:?}", n),
-                                );
-                            }
+                            Err(()) => self.tcx.sess.emit_fatal(errors::UnrecognizedDepNode {
+                                span: attr.span,
+                                name: n,
+                            }),
                         }
                     }
                     None => {
-                        self.tcx.sess.span_fatal(attr.span, "missing DepNode variant");
+                        self.tcx.sess.emit_fatal(errors::MissingDepNode { span: attr.span });
                     }
                 };
                 self.then_this_would_need.push((
@@ -204,7 +201,7 @@ fn check_paths<'tcx>(tcx: TyCtxt<'tcx>, if_this_changed: &Sources, then_this_wou
     // Return early here so as not to construct the query, which is not cheap.
     if if_this_changed.is_empty() {
         for &(target_span, _, _, _) in then_this_would_need {
-            tcx.sess.span_err(target_span, "no `#[rustc_if_this_changed]` annotation detected");
+            tcx.sess.emit_err(errors::MissingIfThisChanged { span: target_span });
         }
         return;
     }
@@ -213,16 +210,13 @@ fn check_paths<'tcx>(tcx: TyCtxt<'tcx>, if_this_changed: &Sources, then_this_wou
             let dependents = query.transitive_predecessors(source_dep_node);
             for &(target_span, ref target_pass, _, ref target_dep_node) in then_this_would_need {
                 if !dependents.contains(&target_dep_node) {
-                    tcx.sess.span_err(
-                        target_span,
-                        &format!(
-                            "no path from `{}` to `{}`",
-                            tcx.def_path_str(source_def_id),
-                            target_pass
-                        ),
-                    );
+                    tcx.sess.emit_err(errors::NoPath {
+                        span: target_span,
+                        source: tcx.def_path_str(source_def_id),
+                        target: *target_pass,
+                    });
                 } else {
-                    tcx.sess.span_err(target_span, "OK");
+                    tcx.sess.emit_err(errors::Ok { span: target_span });
                 }
             }
         }

compiler/rustc_incremental/src/assert_module_sources.rs

@@ -22,6 +22,7 @@
 //! allows for doing a more fine-grained check to see if pre- or post-lto data
 //! was re-used.
 
+use crate::errors;
 use rustc_ast as ast;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def_id::LOCAL_CRATE;
@@ -66,10 +67,9 @@ impl<'tcx> AssertModuleSource<'tcx> {
                 sym::post_dash_lto => (CguReuse::PostLto, ComparisonKind::Exact),
                 sym::any => (CguReuse::PreLto, ComparisonKind::AtLeast),
                 other => {
-                    self.tcx.sess.span_fatal(
-                        attr.span,
-                        &format!("unknown cgu-reuse-kind `{}` specified", other),
-                    );
+                    self.tcx
+                        .sess
+                        .emit_fatal(errors::UnknownReuseKind { span: attr.span, kind: other });
                 }
             }
         } else {
@@ -77,10 +77,7 @@ impl<'tcx> AssertModuleSource<'tcx> {
         };
 
         if !self.tcx.sess.opts.unstable_opts.query_dep_graph {
-            self.tcx.sess.span_fatal(
-                attr.span,
-                "found CGU-reuse attribute but `-Zquery-dep-graph` was not specified",
-            );
+            self.tcx.sess.emit_fatal(errors::MissingQueryDepGraph { span: attr.span });
         }
 
         if !self.check_config(attr) {
@@ -92,13 +89,11 @@ impl<'tcx> AssertModuleSource<'tcx> {
         let crate_name = self.tcx.crate_name(LOCAL_CRATE).to_string();
 
         if !user_path.starts_with(&crate_name) {
-            let msg = format!(
-                "Found malformed codegen unit name `{}`. \
-                Codegen units names must always start with the name of the \
-                crate (`{}` in this case).",
-                user_path, crate_name
-            );
-            self.tcx.sess.span_fatal(attr.span, &msg);
+            self.tcx.sess.emit_fatal(errors::MalformedCguName {
+                span: attr.span,
+                user_path,
+                crate_name,
+            });
         }
 
         // Split of the "special suffix" if there is one.
@@ -125,15 +120,12 @@ impl<'tcx> AssertModuleSource<'tcx> {
             let mut cgu_names: Vec<&str> =
                 self.available_cgus.iter().map(|cgu| cgu.as_str()).collect();
             cgu_names.sort();
-            self.tcx.sess.span_err(
-                attr.span,
-                &format!(
-                    "no module named `{}` (mangled: {}). Available modules: {}",
-                    user_path,
-                    cgu_name,
-                    cgu_names.join(", ")
-                ),
-            );
+            self.tcx.sess.emit_err(errors::NoModuleNamed {
+                span: attr.span,
+                user_path,
+                cgu_name,
+                cgu_names: cgu_names.join(", "),
+            });
         }
 
         self.tcx.sess.cgu_reuse_tracker.set_expectation(
@@ -151,15 +143,15 @@ impl<'tcx> AssertModuleSource<'tcx> {
                 if let Some(value) = item.value_str() {
                     return value;
                 } else {
-                    self.tcx.sess.span_fatal(
-                        item.span(),
-                        &format!("associated value expected for `{}`", name),
-                    );
+                    self.tcx.sess.emit_fatal(errors::FieldAssociatedValueExpected {
+                        span: item.span(),
+                        name,
+                    });
                 }
             }
         }
 
-        self.tcx.sess.span_fatal(attr.span, &format!("no field `{}`", name));
+        self.tcx.sess.emit_fatal(errors::NoField { span: attr.span, name });
     }
 
     /// Scan for a `cfg="foo"` attribute and check whether we have a

compiler/rustc_incremental/src/errors.rs

@@ -0,0 +1,364 @@
+use rustc_macros::Diagnostic;
+use rustc_span::{symbol::Ident, Span, Symbol};
+use std::path::{Path, PathBuf};
+
+#[derive(Diagnostic)]
+#[diag(incremental_unrecognized_depnode)]
+pub struct UnrecognizedDepNode {
+    #[primary_span]
+    pub span: Span,
+    pub name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_missing_depnode)]
+pub struct MissingDepNode {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_missing_if_this_changed)]
+pub struct MissingIfThisChanged {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_ok)]
+pub struct Ok {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_no_path)]
+pub struct NoPath {
+    #[primary_span]
+    pub span: Span,
+    pub target: Symbol,
+    pub source: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_unknown_reuse_kind)]
+pub struct UnknownReuseKind {
+    #[primary_span]
+    pub span: Span,
+    pub kind: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_missing_query_depgraph)]
+pub struct MissingQueryDepGraph {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_malformed_cgu_name)]
+pub struct MalformedCguName {
+    #[primary_span]
+    pub span: Span,
+    pub user_path: String,
+    pub crate_name: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_no_module_named)]
+pub struct NoModuleNamed<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub user_path: &'a str,
+    pub cgu_name: Symbol,
+    pub cgu_names: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_field_associated_value_expected)]
+pub struct FieldAssociatedValueExpected {
+    #[primary_span]
+    pub span: Span,
+    pub name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_no_field)]
+pub struct NoField {
+    #[primary_span]
+    pub span: Span,
+    pub name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_assertion_auto)]
+pub struct AssertionAuto<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub name: &'a str,
+    pub e: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_undefined_clean_dirty_assertions_item)]
+pub struct UndefinedCleanDirtyItem {
+    #[primary_span]
+    pub span: Span,
+    pub kind: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_undefined_clean_dirty_assertions)]
+pub struct UndefinedCleanDirty {
+    #[primary_span]
+    pub span: Span,
+    pub kind: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_repeated_depnode_label)]
+pub struct RepeatedDepNodeLabel<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub label: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_unrecognized_depnode_label)]
+pub struct UnrecognizedDepNodeLabel<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub label: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_not_dirty)]
+pub struct NotDirty<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub dep_node_str: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_not_clean)]
+pub struct NotClean<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub dep_node_str: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_not_loaded)]
+pub struct NotLoaded<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub dep_node_str: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_unknown_item)]
+pub struct UnknownItem {
+    #[primary_span]
+    pub span: Span,
+    pub name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_no_cfg)]
+pub struct NoCfg {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_associated_value_expected_for)]
+pub struct AssociatedValueExpectedFor {
+    #[primary_span]
+    pub span: Span,
+    pub ident: Ident,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_associated_value_expected)]
+pub struct AssociatedValueExpected {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_unchecked_clean)]
+pub struct UncheckedClean {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_delete_old)]
+pub struct DeleteOld<'a> {
+    pub name: &'a str,
+    pub path: PathBuf,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_create_new)]
+pub struct CreateNew<'a> {
+    pub name: &'a str,
+    pub path: PathBuf,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_write_new)]
+pub struct WriteNew<'a> {
+    pub name: &'a str,
+    pub path: PathBuf,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_canonicalize_path)]
+pub struct CanonicalizePath {
+    pub path: PathBuf,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_create_incr_comp_dir)]
+pub struct CreateIncrCompDir<'a> {
+    pub tag: &'a str,
+    pub path: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_create_lock)]
+pub struct CreateLock<'a> {
+    pub lock_err: std::io::Error,
+    pub session_dir: &'a Path,
+    #[note(incremental_lock_unsupported)]
+    pub is_unsupported_lock: Option<()>,
+    #[help(incremental_cargo_help_1)]
+    #[help(incremental_cargo_help_2)]
+    pub is_cargo: Option<()>,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_delete_lock)]
+pub struct DeleteLock<'a> {
+    pub path: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_hard_link_failed)]
+pub struct HardLinkFailed<'a> {
+    pub path: &'a Path,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_delete_partial)]
+pub struct DeletePartial<'a> {
+    pub path: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_delete_full)]
+pub struct DeleteFull<'a> {
+    pub path: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_finalize)]
+pub struct Finalize<'a> {
+    pub path: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_invalid_gc_failed)]
+pub struct InvalidGcFailed<'a> {
+    pub path: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_finalized_gc_failed)]
+pub struct FinalizedGcFailed<'a> {
+    pub path: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_session_gc_failed)]
+pub struct SessionGcFailed<'a> {
+    pub path: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_assert_not_loaded)]
+pub struct AssertNotLoaded;
+
+#[derive(Diagnostic)]
+#[diag(incremental_assert_loaded)]
+pub struct AssertLoaded;
+
+#[derive(Diagnostic)]
+#[diag(incremental_delete_incompatible)]
+pub struct DeleteIncompatible {
+    pub path: PathBuf,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_load_dep_graph)]
+pub struct LoadDepGraph {
+    pub path: PathBuf,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_decode_incr_cache)]
+pub struct DecodeIncrCache {
+    pub err: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_write_dep_graph)]
+pub struct WriteDepGraph<'a> {
+    pub path: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_move_dep_graph)]
+pub struct MoveDepGraph<'a> {
+    pub from: &'a Path,
+    pub to: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_create_dep_graph)]
+pub struct CreateDepGraph<'a> {
+    pub path: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_copy_workproduct_to_cache)]
+pub struct CopyWorkProductToCache<'a> {
+    pub from: &'a Path,
+    pub to: &'a Path,
+    pub err: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(incremental_delete_workproduct)]
+pub struct DeleteWorkProduct<'a> {
+    pub path: &'a Path,
+    pub err: std::io::Error,
+}

compiler/rustc_incremental/src/lib.rs

@@ -2,8 +2,11 @@
 
 #![deny(missing_docs)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
+#![feature(never_type)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
 
 #[macro_use]
 extern crate rustc_middle;
@@ -12,6 +15,7 @@ extern crate tracing;
 
 mod assert_dep_graph;
 pub mod assert_module_sources;
+mod errors;
 mod persist;
 
 use assert_dep_graph::assert_dep_graph;

compiler/rustc_incremental/src/persist/dirty_clean.rs

@@ -19,6 +19,7 @@
 //! Errors are reported if we are in the suitable configuration but
 //! the required condition is not met.
 
+use crate::errors;
 use rustc_ast::{self as ast, Attribute, NestedMetaItem};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def_id::LocalDefId;
@@ -196,11 +197,7 @@ impl<'tcx> DirtyCleanVisitor<'tcx> {
         let loaded_from_disk = self.loaded_from_disk(attr);
         for e in except.iter() {
             if !auto.remove(e) {
-                let msg = format!(
-                    "`except` specified DepNodes that can not be affected for \"{}\": \"{}\"",
-                    name, e
-                );
-                self.tcx.sess.span_fatal(attr.span, &msg);
+                self.tcx.sess.emit_fatal(errors::AssertionAuto { span: attr.span, name, e });
             }
         }
         Assertion { clean: auto, dirty: except, loaded_from_disk }
@@ -282,14 +279,10 @@ impl<'tcx> DirtyCleanVisitor<'tcx> {
                     // An implementation, eg `impl<A> Trait for Foo { .. }`
                     HirItem::Impl { .. } => ("ItemKind::Impl", LABELS_IMPL),
 
-                    _ => self.tcx.sess.span_fatal(
-                        attr.span,
-                        &format!(
-                            "clean/dirty auto-assertions not yet defined \
-                             for Node::Item.node={:?}",
-                            item.kind
-                        ),
-                    ),
+                    _ => self.tcx.sess.emit_fatal(errors::UndefinedCleanDirtyItem {
+                        span: attr.span,
+                        kind: format!("{:?}", item.kind),
+                    }),
                 }
             }
             HirNode::TraitItem(item) => match item.kind {
@@ -302,10 +295,10 @@ impl<'tcx> DirtyCleanVisitor<'tcx> {
                 ImplItemKind::Const(..) => ("NodeImplConst", LABELS_CONST_IN_IMPL),
                 ImplItemKind::Type(..) => ("NodeImplType", LABELS_CONST_IN_IMPL),
             },
-            _ => self.tcx.sess.span_fatal(
-                attr.span,
-                &format!("clean/dirty auto-assertions not yet defined for {:?}", node),
-            ),
+            _ => self.tcx.sess.emit_fatal(errors::UndefinedCleanDirty {
+                span: attr.span,
+                kind: format!("{:?}", node),
+            }),
         };
         let labels =
             Labels::from_iter(labels.iter().flat_map(|s| s.iter().map(|l| (*l).to_string())));
@@ -318,16 +311,15 @@ impl<'tcx> DirtyCleanVisitor<'tcx> {
             let label = label.trim();
             if DepNode::has_label_string(label) {
                 if out.contains(label) {
-                    self.tcx.sess.span_fatal(
-                        item.span(),
-                        &format!("dep-node label `{}` is repeated", label),
-                    );
+                    self.tcx
+                        .sess
+                        .emit_fatal(errors::RepeatedDepNodeLabel { span: item.span(), label });
                 }
                 out.insert(label.to_string());
             } else {
                 self.tcx
                     .sess
-                    .span_fatal(item.span(), &format!("dep-node label `{}` not recognized", label));
+                    .emit_fatal(errors::UnrecognizedDepNodeLabel { span: item.span(), label });
             }
         }
         out
@@ -348,7 +340,7 @@ impl<'tcx> DirtyCleanVisitor<'tcx> {
             let dep_node_str = self.dep_node_str(&dep_node);
             self.tcx
                 .sess
-                .span_err(item_span, &format!("`{}` should be dirty but is not", dep_node_str));
+                .emit_err(errors::NotDirty { span: item_span, dep_node_str: &dep_node_str });
         }
     }
 
@@ -359,7 +351,7 @@ impl<'tcx> DirtyCleanVisitor<'tcx> {
             let dep_node_str = self.dep_node_str(&dep_node);
             self.tcx
                 .sess
-                .span_err(item_span, &format!("`{}` should be clean but is not", dep_node_str));
+                .emit_err(errors::NotClean { span: item_span, dep_node_str: &dep_node_str });
         }
     }
 
@@ -368,10 +360,9 @@ impl<'tcx> DirtyCleanVisitor<'tcx> {
 
         if !self.tcx.dep_graph.debug_was_loaded_from_disk(dep_node) {
             let dep_node_str = self.dep_node_str(&dep_node);
-            self.tcx.sess.span_err(
-                item_span,
-                &format!("`{}` should have been loaded from disk but it was not", dep_node_str),
-            );
+            self.tcx
+                .sess
+                .emit_err(errors::NotLoaded { span: item_span, dep_node_str: &dep_node_str });
         }
     }
 
@@ -412,12 +403,12 @@ fn check_config(tcx: TyCtxt<'_>, attr: &Attribute) -> bool {
             debug!("check_config: searching for cfg {:?}", value);
             cfg = Some(config.contains(&(value, None)));
         } else if !(item.has_name(EXCEPT) || item.has_name(LOADED_FROM_DISK)) {
-            tcx.sess.span_err(attr.span, &format!("unknown item `{}`", item.name_or_empty()));
+            tcx.sess.emit_err(errors::UnknownItem { span: attr.span, name: item.name_or_empty() });
         }
     }
 
     match cfg {
-        None => tcx.sess.span_fatal(attr.span, "no cfg attribute"),
+        None => tcx.sess.emit_fatal(errors::NoCfg { span: attr.span }),
         Some(c) => c,
     }
 }
@@ -426,13 +417,11 @@ fn expect_associated_value(tcx: TyCtxt<'_>, item: &NestedMetaItem) -> Symbol {
     if let Some(value) = item.value_str() {
         value
     } else {
-        let msg = if let Some(ident) = item.ident() {
-            format!("associated value expected for `{}`", ident)
+        if let Some(ident) = item.ident() {
+            tcx.sess.emit_fatal(errors::AssociatedValueExpectedFor { span: item.span(), ident });
         } else {
-            "expected an associated value".to_string()
-        };
-
-        tcx.sess.span_fatal(item.span(), &msg);
+            tcx.sess.emit_fatal(errors::AssociatedValueExpected { span: item.span() });
+        }
     }
 }
 
@@ -456,7 +445,7 @@ impl<'tcx> FindAllAttrs<'tcx> {
     fn report_unchecked_attrs(&self, mut checked_attrs: FxHashSet<ast::AttrId>) {
         for attr in &self.found_attrs {
             if !checked_attrs.contains(&attr.id) {
-                self.tcx.sess.span_err(attr.span, "found unchecked `#[rustc_clean]` attribute");
+                self.tcx.sess.emit_err(errors::UncheckedClean { span: attr.span });
                 checked_attrs.insert(attr.id);
             }
         }

compiler/rustc_incremental/src/persist/file_format.rs

@@ -9,15 +9,15 @@
 //! compiler versions don't change frequently for the typical user, being
 //! conservative here practically has no downside.
 
-use std::env;
-use std::fs;
-use std::io::{self, Read};
-use std::path::{Path, PathBuf};
-
+use crate::errors;
 use rustc_data_structures::memmap::Mmap;
 use rustc_serialize::opaque::{FileEncodeResult, FileEncoder};
 use rustc_serialize::Encoder;
 use rustc_session::Session;
+use std::env;
+use std::fs;
+use std::io::{self, Read};
+use std::path::{Path, PathBuf};
 
 /// The first few bytes of files generated by incremental compilation.
 const FILE_MAGIC: &[u8] = b"RSIC";
@@ -60,12 +60,7 @@ where
         }
         Err(err) if err.kind() == io::ErrorKind::NotFound => (),
         Err(err) => {
-            sess.err(&format!(
-                "unable to delete old {} at `{}`: {}",
-                name,
-                path_buf.display(),
-                err
-            ));
+            sess.emit_err(errors::DeleteOld { name, path: path_buf, err });
             return;
         }
     }
@@ -73,7 +68,7 @@ where
     let mut encoder = match FileEncoder::new(&path_buf) {
         Ok(encoder) => encoder,
         Err(err) => {
-            sess.err(&format!("failed to create {} at `{}`: {}", name, path_buf.display(), err));
+            sess.emit_err(errors::CreateNew { name, path: path_buf, err });
             return;
         }
     };
@@ -90,7 +85,7 @@ where
             debug!("save: data written to disk successfully");
         }
         Err(err) => {
-            sess.err(&format!("failed to write {} to `{}`: {}", name, path_buf.display(), err));
+            sess.emit_err(errors::WriteNew { name, path: path_buf, err });
         }
     }
 }

compiler/rustc_incremental/src/persist/fs.rs

@@ -103,6 +103,7 @@
 //! unsupported file system and emit a warning in that case. This is not yet
 //! implemented.
 
+use crate::errors;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::{base_n, flock};
@@ -225,12 +226,7 @@ pub fn prepare_session_directory(
     let crate_dir = match crate_dir.canonicalize() {
         Ok(v) => v,
         Err(err) => {
-            let reported = sess.err(&format!(
-                "incremental compilation: error canonicalizing path `{}`: {}",
-                crate_dir.display(),
-                err
-            ));
-            return Err(reported);
+            return Err(sess.emit_err(errors::CanonicalizePath { path: crate_dir, err }));
         }
     };
 
@@ -273,14 +269,7 @@ pub fn prepare_session_directory(
             debug!("successfully copied data from: {}", source_directory.display());
 
             if !allows_links {
-                sess.warn(&format!(
-                    "Hard linking files in the incremental \
-                                        compilation cache failed. Copying files \
-                                        instead. Consider moving the cache \
-                                        directory to a file system which supports \
-                                        hard linking in session dir `{}`",
-                    session_dir.display()
-                ));
+                sess.emit_warning(errors::HardLinkFailed { path: &session_dir });
             }
 
             sess.init_incr_comp_session(session_dir, directory_lock, true);
@@ -295,12 +284,7 @@ pub fn prepare_session_directory(
             // Try to remove the session directory we just allocated. We don't
             // know if there's any garbage in it from the failed copy action.
             if let Err(err) = safe_remove_dir_all(&session_dir) {
-                sess.warn(&format!(
-                    "Failed to delete partly initialized \
-                                    session dir `{}`: {}",
-                    session_dir.display(),
-                    err
-                ));
+                sess.emit_warning(errors::DeletePartial { path: &session_dir, err });
             }
 
             delete_session_dir_lock_file(sess, &lock_file_path);
@@ -332,12 +316,7 @@ pub fn finalize_session_directory(sess: &Session, svh: Svh) {
         );
 
         if let Err(err) = safe_remove_dir_all(&*incr_comp_session_dir) {
-            sess.warn(&format!(
-                "Error deleting incremental compilation \
-                                session directory `{}`: {}",
-                incr_comp_session_dir.display(),
-                err
-            ));
+            sess.emit_warning(errors::DeleteFull { path: &incr_comp_session_dir, err });
         }
 
         let lock_file_path = lock_file_path(&*incr_comp_session_dir);
@@ -380,12 +359,7 @@ pub fn finalize_session_directory(sess: &Session, svh: Svh) {
         }
         Err(e) => {
             // Warn about the error. However, no need to abort compilation now.
-            sess.warn(&format!(
-                "Error finalizing incremental compilation \
-                               session directory `{}`: {}",
-                incr_comp_session_dir.display(),
-                e
-            ));
+            sess.emit_warning(errors::Finalize { path: &incr_comp_session_dir, err: e });
 
             debug!("finalize_session_directory() - error, marking as invalid");
             // Drop the file lock, so we can garage collect
@@ -488,16 +462,7 @@ fn create_dir(sess: &Session, path: &Path, dir_tag: &str) -> Result<(), ErrorGua
             debug!("{} directory created successfully", dir_tag);
             Ok(())
         }
-        Err(err) => {
-            let reported = sess.err(&format!(
-                "Could not create incremental compilation {} \
-                               directory `{}`: {}",
-                dir_tag,
-                path.display(),
-                err
-            ));
-            Err(reported)
-        }
+        Err(err) => Err(sess.emit_err(errors::CreateIncrCompDir { tag: dir_tag, path, err })),
     }
 }
 
@@ -518,46 +483,20 @@ fn lock_directory(
         // the lock should be exclusive
         Ok(lock) => Ok((lock, lock_file_path)),
         Err(lock_err) => {
-            let mut err = sess.struct_err(&format!(
-                "incremental compilation: could not create \
-                 session directory lock file: {}",
-                lock_err
-            ));
-            if flock::Lock::error_unsupported(&lock_err) {
-                err.note(&format!(
-                    "the filesystem for the incremental path at {} \
-                     does not appear to support locking, consider changing the \
-                     incremental path to a filesystem that supports locking \
-                     or disable incremental compilation",
-                    session_dir.display()
-                ));
-                if std::env::var_os("CARGO").is_some() {
-                    err.help(
-                        "incremental compilation can be disabled by setting the \
-                         environment variable CARGO_INCREMENTAL=0 (see \
-                         https://doc.rust-lang.org/cargo/reference/profiles.html#incremental)",
-                    );
-                    err.help(
-                        "the entire build directory can be changed to a different \
-                        filesystem by setting the environment variable CARGO_TARGET_DIR \
-                        to a different path (see \
-                        https://doc.rust-lang.org/cargo/reference/config.html#buildtarget-dir)",
-                    );
-                }
-            }
-            Err(err.emit())
+            let is_unsupported_lock = flock::Lock::error_unsupported(&lock_err).then_some(());
+            Err(sess.emit_err(errors::CreateLock {
+                lock_err,
+                session_dir,
+                is_unsupported_lock,
+                is_cargo: std::env::var_os("CARGO").map(|_| ()),
+            }))
         }
     }
 }
 
 fn delete_session_dir_lock_file(sess: &Session, lock_file_path: &Path) {
     if let Err(err) = safe_remove_file(&lock_file_path) {
-        sess.warn(&format!(
-            "Error deleting lock file for incremental \
-                            compilation session directory `{}`: {}",
-            lock_file_path.display(),
-            err
-        ));
+        sess.emit_warning(errors::DeleteLock { path: lock_file_path, err });
     }
 }
 
@@ -774,12 +713,7 @@ pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
         if !lock_file_to_session_dir.values().any(|dir| *dir == directory_name) {
             let path = crate_directory.join(directory_name);
             if let Err(err) = safe_remove_dir_all(&path) {
-                sess.warn(&format!(
-                    "Failed to garbage collect invalid incremental \
-                                    compilation session directory `{}`: {}",
-                    path.display(),
-                    err
-                ));
+                sess.emit_warning(errors::InvalidGcFailed { path: &path, err });
             }
         }
     }
@@ -885,12 +819,7 @@ pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
         debug!("garbage_collect_session_directories() - deleting `{}`", path.display());
 
         if let Err(err) = safe_remove_dir_all(&path) {
-            sess.warn(&format!(
-                "Failed to garbage collect finalized incremental \
-                                compilation session directory `{}`: {}",
-                path.display(),
-                err
-            ));
+            sess.emit_warning(errors::FinalizedGcFailed { path: &path, err });
         } else {
             delete_session_dir_lock_file(sess, &lock_file_path(&path));
         }
@@ -907,11 +836,7 @@ fn delete_old(sess: &Session, path: &Path) {
     debug!("garbage_collect_session_directories() - deleting `{}`", path.display());
 
     if let Err(err) = safe_remove_dir_all(&path) {
-        sess.warn(&format!(
-            "Failed to garbage collect incremental compilation session directory `{}`: {}",
-            path.display(),
-            err
-        ));
+        sess.emit_warning(errors::SessionGcFailed { path: &path, err });
     } else {
         delete_session_dir_lock_file(sess, &lock_file_path(&path));
     }

compiler/rustc_incremental/src/persist/load.rs

@@ -1,5 +1,6 @@
 //! Code to save/load the dep-graph from files.
 
+use crate::errors;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::memmap::Mmap;
 use rustc_middle::dep_graph::{SerializedDepGraph, WorkProduct, WorkProductId};
@@ -8,7 +9,7 @@ use rustc_serialize::opaque::MemDecoder;
 use rustc_serialize::Decodable;
 use rustc_session::config::IncrementalStateAssertion;
 use rustc_session::Session;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
 use super::data::*;
 use super::file_format;
@@ -27,11 +28,10 @@ pub enum LoadResult<T> {
     },
     /// The file either didn't exist or was produced by an incompatible compiler version.
     DataOutOfDate,
-    /// An error occurred.
-    Error {
-        #[allow(missing_docs)]
-        message: String,
-    },
+    /// Loading the dep graph failed.
+    LoadDepGraph(PathBuf, std::io::Error),
+    /// Decoding loaded incremental cache failed.
+    DecodeIncrCache(Box<dyn std::any::Any + Send>),
 }
 
 impl<T: Default> LoadResult<T> {
@@ -40,36 +40,31 @@ impl<T: Default> LoadResult<T> {
         // Check for errors when using `-Zassert-incremental-state`
         match (sess.opts.assert_incr_state, &self) {
             (Some(IncrementalStateAssertion::NotLoaded), LoadResult::Ok { .. }) => {
-                sess.fatal(
-                    "We asserted that the incremental cache should not be loaded, \
-                         but it was loaded.",
-                );
+                sess.emit_fatal(errors::AssertNotLoaded);
             }
             (
                 Some(IncrementalStateAssertion::Loaded),
-                LoadResult::Error { .. } | LoadResult::DataOutOfDate,
+                LoadResult::LoadDepGraph(..)
+                | LoadResult::DecodeIncrCache(..)
+                | LoadResult::DataOutOfDate,
             ) => {
-                sess.fatal(
-                    "We asserted that an existing incremental cache directory should \
-                         be successfully loaded, but it was not.",
-                );
+                sess.emit_fatal(errors::AssertLoaded);
             }
             _ => {}
         };
 
         match self {
-            LoadResult::Error { message } => {
-                sess.warn(&message);
+            LoadResult::LoadDepGraph(path, err) => {
+                sess.emit_warning(errors::LoadDepGraph { path, err });
+                Default::default()
+            }
+            LoadResult::DecodeIncrCache(err) => {
+                sess.emit_warning(errors::DecodeIncrCache { err: format!("{err:?}") });
                 Default::default()
             }
             LoadResult::DataOutOfDate => {
                 if let Err(err) = delete_all_session_dir_contents(sess) {
-                    sess.err(&format!(
-                        "Failed to delete invalidated or incompatible \
-                         incremental compilation session directory contents `{}`: {}.",
-                        dep_graph_path(sess).display(),
-                        err
-                    ));
+                    sess.emit_err(errors::DeleteIncompatible { path: dep_graph_path(sess), err });
                 }
                 Default::default()
             }
@@ -90,9 +85,7 @@ fn load_data(
             // compiler version. Neither is an error.
             LoadResult::DataOutOfDate
         }
-        Err(err) => LoadResult::Error {
-            message: format!("could not load dep-graph from `{}`: {}", path.display(), err),
-        },
+        Err(err) => LoadResult::LoadDepGraph(path.to_path_buf(), err),
     }
 }
 
@@ -114,9 +107,9 @@ impl<T> MaybeAsync<LoadResult<T>> {
     pub fn open(self) -> LoadResult<T> {
         match self {
             MaybeAsync::Sync(result) => result,
-            MaybeAsync::Async(handle) => handle.join().unwrap_or_else(|e| LoadResult::Error {
-                message: format!("could not decode incremental cache: {:?}", e),
-            }),
+            MaybeAsync::Async(handle) => {
+                handle.join().unwrap_or_else(|e| LoadResult::DecodeIncrCache(e))
+            }
         }
     }
 }
@@ -185,7 +178,8 @@ pub fn load_dep_graph(sess: &Session) -> DepGraphFuture {
 
         match load_data(report_incremental_info, &path, nightly_build) {
             LoadResult::DataOutOfDate => LoadResult::DataOutOfDate,
-            LoadResult::Error { message } => LoadResult::Error { message },
+            LoadResult::LoadDepGraph(path, err) => LoadResult::LoadDepGraph(path, err),
+            LoadResult::DecodeIncrCache(err) => LoadResult::DecodeIncrCache(err),
             LoadResult::Ok { data: (bytes, start_pos) } => {
                 let mut decoder = MemDecoder::new(&bytes, start_pos);
                 let prev_commandline_args_hash = u64::decode(&mut decoder);

compiler/rustc_incremental/src/persist/save.rs

@@ -1,3 +1,4 @@
+use crate::errors;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::join;
 use rustc_middle::dep_graph::{DepGraph, SerializedDepGraph, WorkProduct, WorkProductId};
@@ -59,19 +60,14 @@ pub fn save_dep_graph(tcx: TyCtxt<'_>) {
             move || {
                 sess.time("incr_comp_persist_dep_graph", || {
                     if let Err(err) = tcx.dep_graph.encode(&tcx.sess.prof) {
-                        sess.err(&format!(
-                            "failed to write dependency graph to `{}`: {}",
-                            staging_dep_graph_path.display(),
-                            err
-                        ));
+                        sess.emit_err(errors::WriteDepGraph { path: &staging_dep_graph_path, err });
                     }
                     if let Err(err) = fs::rename(&staging_dep_graph_path, &dep_graph_path) {
-                        sess.err(&format!(
-                            "failed to move dependency graph from `{}` to `{}`: {}",
-                            staging_dep_graph_path.display(),
-                            dep_graph_path.display(),
-                            err
-                        ));
+                        sess.emit_err(errors::MoveDepGraph {
+                            from: &staging_dep_graph_path,
+                            to: &dep_graph_path,
+                            err,
+                        });
                     }
                 });
             },
@@ -163,11 +159,7 @@ pub fn build_dep_graph(
     let mut encoder = match FileEncoder::new(&path_buf) {
         Ok(encoder) => encoder,
         Err(err) => {
-            sess.err(&format!(
-                "failed to create dependency graph at `{}`: {}",
-                path_buf.display(),
-                err
-            ));
+            sess.emit_err(errors::CreateDepGraph { path: &path_buf, err });
             return None;
         }
     };

compiler/rustc_incremental/src/persist/work_product.rs

@@ -2,6 +2,7 @@
 //!
 //! [work products]: WorkProduct
 
+use crate::errors;
 use crate::persist::fs::*;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_fs_util::link_or_copy;
@@ -28,12 +29,11 @@ pub fn copy_cgu_workproduct_to_incr_comp_cache_dir(
                 let _ = saved_files.insert(ext.to_string(), file_name);
             }
             Err(err) => {
-                sess.warn(&format!(
-                    "error copying object file `{}` to incremental directory as `{}`: {}",
-                    path.display(),
-                    path_in_incr_dir.display(),
-                    err
-                ));
+                sess.emit_warning(errors::CopyWorkProductToCache {
+                    from: &path,
+                    to: &path_in_incr_dir,
+                    err,
+                });
             }
         }
     }
@@ -49,11 +49,7 @@ pub fn delete_workproduct_files(sess: &Session, work_product: &WorkProduct) {
     for (_, path) in &work_product.saved_files {
         let path = in_incr_comp_dir_sess(sess, path);
         if let Err(err) = std_fs::remove_file(&path) {
-            sess.warn(&format!(
-                "file-system error deleting outdated file `{}`: {}",
-                path.display(),
-                err
-            ));
+            sess.emit_warning(errors::DeleteWorkProduct { path: &path, err });
         }
     }
 }

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -67,6 +67,7 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::Node;
 use rustc_middle::dep_graph::DepContext;
+use rustc_middle::ty::print::with_forced_trimmed_paths;
 use rustc_middle::ty::relate::{self, RelateResult, TypeRelation};
 use rustc_middle::ty::{
     self, error::TypeError, List, Region, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable,
@@ -1612,16 +1613,31 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 {
                     format!("expected this to be `{}`", expected)
                 } else {
-                    terr.to_string()
+                    terr.to_string(self.tcx).to_string()
                 };
                 label_or_note(sp, &terr);
                 label_or_note(span, &msg);
             } else {
-                label_or_note(span, &terr.to_string());
+                label_or_note(span, &terr.to_string(self.tcx));
                 label_or_note(sp, &msg);
             }
         } else {
-            label_or_note(span, &terr.to_string());
+            if let Some(values) = values
+                && let Some((e, f)) = values.ty()
+                && let TypeError::ArgumentSorts(..) | TypeError::Sorts(_) = terr
+            {
+                let e = self.tcx.erase_regions(e);
+                let f = self.tcx.erase_regions(f);
+                let expected = with_forced_trimmed_paths!(e.sort_string(self.tcx));
+                let found = with_forced_trimmed_paths!(f.sort_string(self.tcx));
+                if expected == found {
+                    label_or_note(span, &terr.to_string(self.tcx));
+                } else {
+                    label_or_note(span, &format!("expected {expected}, found {found}"));
+                }
+            } else {
+                label_or_note(span, &terr.to_string(self.tcx));
+            }
         }
 
         if let Some((expected, found, exp_p, found_p)) = expected_found {
@@ -1849,6 +1865,18 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         self.check_and_note_conflicting_crates(diag, terr);
 
         self.note_and_explain_type_err(diag, terr, cause, span, cause.body_id.to_def_id());
+        if let Some(exp_found) = exp_found
+            && let exp_found = TypeError::Sorts(exp_found)
+            && exp_found != terr
+        {
+            self.note_and_explain_type_err(
+                diag,
+                exp_found,
+                cause,
+                span,
+                cause.body_id.to_def_id(),
+            );
+        }
 
         if let Some(ValuePairs::PolyTraitRefs(exp_found)) = values
             && let ty::Closure(def_id, _) = exp_found.expected.skip_binder().self_ty().kind()

compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs

@@ -137,25 +137,25 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                             diag.help(
                                 "given a type parameter `T` and a method `foo`:
 ```
-trait Trait<T> { fn foo(&tcx) -> T; }
+trait Trait<T> { fn foo(&self) -> T; }
 ```
 the only ways to implement method `foo` are:
 - constrain `T` with an explicit type:
 ```
 impl Trait<String> for X {
-    fn foo(&tcx) -> String { String::new() }
+    fn foo(&self) -> String { String::new() }
 }
 ```
 - add a trait bound to `T` and call a method on that trait that returns `Self`:
 ```
 impl<T: std::default::Default> Trait<T> for X {
-    fn foo(&tcx) -> T { <T as std::default::Default>::default() }
+    fn foo(&self) -> T { <T as std::default::Default>::default() }
 }
 ```
 - change `foo` to return an argument of type `T`:
 ```
 impl<T> Trait<T> for X {
-    fn foo(&tcx, x: T) -> T { x }
+    fn foo(&self, x: T) -> T { x }
 }
 ```",
                             );
@@ -218,6 +218,13 @@ impl<T> Trait<T> for X {
                             );
                         }
                     }
+                    (ty::FnPtr(_), ty::FnDef(def, _))
+                    if let hir::def::DefKind::Fn = tcx.def_kind(def) => {
+                        diag.note(
+                            "when the arguments and return types match, functions can be coerced \
+                             to function pointers",
+                        );
+                    }
                     _ => {}
                 }
                 debug!(
@@ -389,14 +396,14 @@ impl<T> Trait<T> for X {
 ```
 trait Trait {
 type T;
-fn foo(&tcx) -> Self::T;
+fn foo(&self) -> Self::T;
 }
 ```
 the only way of implementing method `foo` is to constrain `T` with an explicit associated type:
 ```
 impl Trait for X {
 type T = String;
-fn foo(&tcx) -> Self::T { String::new() }
+fn foo(&self) -> Self::T { String::new() }
 }
 ```",
             );

compiler/rustc_infer/src/infer/error_reporting/suggest.rs

@@ -404,7 +404,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                         (msg, sug)
                     }
                 };
-                diag.span_suggestion(span, msg, sug, Applicability::MaybeIncorrect);
+                diag.span_suggestion_verbose(span, msg, sug, Applicability::MaybeIncorrect);
             }
             (ty::FnDef(did1, substs1), ty::FnDef(did2, substs2)) => {
                 let expected_sig =

compiler/rustc_infer/src/infer/higher_ranked/mod.rs

@@ -90,7 +90,7 @@ impl<'tcx> InferCtxt<'tcx> {
             types: &mut |bound_ty: ty::BoundTy| {
                 self.tcx.mk_ty(ty::Placeholder(ty::PlaceholderType {
                     universe: next_universe,
-                    name: bound_ty.var,
+                    name: bound_ty.kind,
                 }))
             },
             consts: &mut |bound_var: ty::BoundVar, ty| {

compiler/rustc_infer/src/infer/mod.rs

@@ -2044,7 +2044,7 @@ fn replace_param_and_infer_substs_with_placeholder<'tcx>(
 ) -> SubstsRef<'tcx> {
     struct ReplaceParamAndInferWithPlaceholder<'tcx> {
         tcx: TyCtxt<'tcx>,
-        idx: usize,
+        idx: u32,
     }
 
     impl<'tcx> TypeFolder<'tcx> for ReplaceParamAndInferWithPlaceholder<'tcx> {
@@ -2056,7 +2056,7 @@ fn replace_param_and_infer_substs_with_placeholder<'tcx>(
             if let ty::Infer(_) = t.kind() {
                 self.tcx.mk_ty(ty::Placeholder(ty::PlaceholderType {
                     universe: ty::UniverseIndex::ROOT,
-                    name: ty::BoundVar::from_usize({
+                    name: ty::BoundTyKind::Anon({
                         let idx = self.idx;
                         self.idx += 1;
                         idx
@@ -2077,7 +2077,7 @@ fn replace_param_and_infer_substs_with_placeholder<'tcx>(
                 self.tcx.mk_const(
                     ty::PlaceholderConst {
                         universe: ty::UniverseIndex::ROOT,
-                        name: ty::BoundVar::from_usize({
+                        name: ty::BoundVar::from_u32({
                             let idx = self.idx;
                             self.idx += 1;
                             idx

compiler/rustc_interface/Cargo.toml

@@ -49,9 +49,6 @@ rustc_target = { path = "../rustc_target" }
 rustc_trait_selection = { path = "../rustc_trait_selection" }
 rustc_ty_utils = { path = "../rustc_ty_utils" }
 
-[dev-dependencies]
-rustc_target = { path = "../rustc_target" }
-
 [features]
 llvm = ['rustc_codegen_llvm']
 rustc_use_parallel_compiler = ['rayon', 'rustc-rayon-core', 'rustc_query_impl/rustc_use_parallel_compiler', 'rustc_errors/rustc_use_parallel_compiler']

compiler/rustc_interface/src/errors.rs

@@ -1,5 +1,7 @@
 use rustc_macros::Diagnostic;
+use rustc_session::config::CrateType;
 use rustc_span::{Span, Symbol};
+use rustc_target::spec::TargetTriple;
 
 use std::io;
 use std::path::Path;
@@ -91,3 +93,22 @@ pub struct FailedWritingFile<'a> {
 #[derive(Diagnostic)]
 #[diag(interface_proc_macro_crate_panic_abort)]
 pub struct ProcMacroCratePanicAbort;
+
+#[derive(Diagnostic)]
+#[diag(interface_unsupported_crate_type_for_target)]
+pub struct UnsupportedCrateTypeForTarget<'a> {
+    pub crate_type: CrateType,
+    pub target_triple: &'a TargetTriple,
+}
+
+#[derive(Diagnostic)]
+#[diag(interface_multiple_output_types_adaption)]
+pub struct MultipleOutputTypesAdaption;
+
+#[derive(Diagnostic)]
+#[diag(interface_ignoring_extra_filename)]
+pub struct IgnoringExtraFilename;
+
+#[derive(Diagnostic)]
+#[diag(interface_ignoring_out_dir)]
+pub struct IgnoringOutDir;

compiler/rustc_interface/src/util.rs

@@ -1,3 +1,4 @@
+use crate::errors;
 use info;
 use libloading::Library;
 use rustc_ast as ast;
@@ -472,16 +473,15 @@ pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<C
     }
 
     base.retain(|crate_type| {
-        let res = !output::invalid_output_for_target(session, *crate_type);
-
-        if !res {
-            session.warn(&format!(
-                "dropping unsupported crate type `{}` for target `{}`",
-                *crate_type, session.opts.target_triple
-            ));
+        if output::invalid_output_for_target(session, *crate_type) {
+            session.emit_warning(errors::UnsupportedCrateTypeForTarget {
+                crate_type: *crate_type,
+                target_triple: &session.opts.target_triple,
+            });
+            false
+        } else {
+            true
         }
-
-        res
     });
 
     base
@@ -517,19 +517,16 @@ pub fn build_output_filenames(attrs: &[ast::Attribute], sess: &Session) -> Outpu
             let unnamed_output_types =
                 sess.opts.output_types.values().filter(|a| a.is_none()).count();
             let ofile = if unnamed_output_types > 1 {
-                sess.warn(
-                    "due to multiple output types requested, the explicitly specified \
-                     output file name will be adapted for each output type",
-                );
+                sess.emit_warning(errors::MultipleOutputTypesAdaption);
                 None
             } else {
                 if !sess.opts.cg.extra_filename.is_empty() {
-                    sess.warn("ignoring -C extra-filename flag due to -o flag");
+                    sess.emit_warning(errors::IgnoringExtraFilename);
                 }
                 Some(out_file.clone())
             };
             if sess.io.output_dir != None {
-                sess.warn("ignoring --out-dir flag due to -o flag");
+                sess.emit_warning(errors::IgnoringOutDir);
             }
 
             OutputFilenames::new(

compiler/rustc_lint/src/builtin.rs

@@ -580,27 +580,28 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
     }
 
     fn check_impl_item(&mut self, cx: &LateContext<'_>, impl_item: &hir::ImplItem<'_>) {
-        // If the method is an impl for a trait, don't doc.
         let context = method_context(cx, impl_item.owner_id.def_id);
-        if context == MethodLateContext::TraitImpl {
-            return;
-        }
 
-        // If the method is an impl for an item with docs_hidden, don't doc.
-        if context == MethodLateContext::PlainImpl {
-            let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id());
-            let impl_ty = cx.tcx.type_of(parent);
-            let outerdef = match impl_ty.kind() {
-                ty::Adt(def, _) => Some(def.did()),
-                ty::Foreign(def_id) => Some(*def_id),
-                _ => None,
-            };
-            let is_hidden = match outerdef {
-                Some(id) => cx.tcx.is_doc_hidden(id),
-                None => false,
-            };
-            if is_hidden {
-                return;
+        match context {
+            // If the method is an impl for a trait, don't doc.
+            MethodLateContext::TraitImpl => return,
+            MethodLateContext::TraitAutoImpl => {}
+            // If the method is an impl for an item with docs_hidden, don't doc.
+            MethodLateContext::PlainImpl => {
+                let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id());
+                let impl_ty = cx.tcx.type_of(parent);
+                let outerdef = match impl_ty.kind() {
+                    ty::Adt(def, _) => Some(def.did()),
+                    ty::Foreign(def_id) => Some(*def_id),
+                    _ => None,
+                };
+                let is_hidden = match outerdef {
+                    Some(id) => cx.tcx.is_doc_hidden(id),
+                    None => false,
+                };
+                if is_hidden {
+                    return;
+                }
             }
         }
 

compiler/rustc_lint/src/lib.rs

@@ -324,7 +324,6 @@ fn register_builtins(store: &mut LintStore) {
     store.register_renamed("exceeding_bitshifts", "arithmetic_overflow");
     store.register_renamed("redundant_semicolon", "redundant_semicolons");
     store.register_renamed("overlapping_patterns", "overlapping_range_endpoints");
-    store.register_renamed("safe_packed_borrows", "unaligned_references");
     store.register_renamed("disjoint_capture_migration", "rust_2021_incompatible_closure_captures");
     store.register_renamed("or_patterns_back_compat", "rust_2021_incompatible_or_patterns");
     store.register_renamed("non_fmt_panic", "non_fmt_panics");
@@ -487,6 +486,16 @@ fn register_builtins(store: &mut LintStore) {
         "converted into hard error, see issue #71800 \
          <https://github.com/rust-lang/rust/issues/71800> for more information",
     );
+    store.register_removed(
+        "safe_packed_borrows",
+        "converted into hard error, see issue #82523 \
+         <https://github.com/rust-lang/rust/issues/82523> for more information",
+    );
+    store.register_removed(
+        "unaligned_references",
+        "converted into hard error, see issue #82523 \
+         <https://github.com/rust-lang/rust/issues/82523> for more information",
+    );
 }
 
 fn register_internals(store: &mut LintStore) {

compiler/rustc_lint_defs/src/builtin.rs

@@ -1187,51 +1187,6 @@ declare_lint! {
     "lints that have been renamed or removed"
 }
 
-declare_lint! {
-    /// The `unaligned_references` lint detects unaligned references to fields
-    /// of [packed] structs.
-    ///
-    /// [packed]: https://doc.rust-lang.org/reference/type-layout.html#the-alignment-modifiers
-    ///
-    /// ### Example
-    ///
-    /// ```rust,compile_fail
-    /// #[repr(packed)]
-    /// pub struct Foo {
-    ///     field1: u64,
-    ///     field2: u8,
-    /// }
-    ///
-    /// fn main() {
-    ///     unsafe {
-    ///         let foo = Foo { field1: 0, field2: 0 };
-    ///         let _ = &foo.field1;
-    ///         println!("{}", foo.field1); // An implicit `&` is added here, triggering the lint.
-    ///     }
-    /// }
-    /// ```
-    ///
-    /// {{produces}}
-    ///
-    /// ### Explanation
-    ///
-    /// Creating a reference to an insufficiently aligned packed field is [undefined behavior] and
-    /// should be disallowed. Using an `unsafe` block does not change anything about this. Instead,
-    /// the code should do a copy of the data in the packed field or use raw pointers and unaligned
-    /// accesses. See [issue #82523] for more information.
-    ///
-    /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
-    /// [issue #82523]: https://github.com/rust-lang/rust/issues/82523
-    pub UNALIGNED_REFERENCES,
-    Deny,
-    "detects unaligned references to fields of packed structs",
-    @future_incompatible = FutureIncompatibleInfo {
-        reference: "issue #82523 <https://github.com/rust-lang/rust/issues/82523>",
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportNow,
-    };
-    report_in_external_macro
-}
-
 declare_lint! {
     /// The `const_item_mutation` lint detects attempts to mutate a `const`
     /// item.
@@ -3308,7 +3263,6 @@ declare_lint_pass! {
         PUB_USE_OF_PRIVATE_EXTERN_CRATE,
         INVALID_TYPE_PARAM_DEFAULT,
         RENAMED_AND_REMOVED_LINTS,
-        UNALIGNED_REFERENCES,
         CONST_ITEM_MUTATION,
         PATTERNS_IN_FNS_WITHOUT_BODY,
         MISSING_FRAGMENT_SPECIFIER,

compiler/rustc_metadata/src/dependency_format.rs

@@ -113,37 +113,37 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
         CrateType::Staticlib => Linkage::Static,
     };
 
-    if preferred_linkage == Linkage::NotLinked {
+    match preferred_linkage {
         // If the crate is not linked, there are no link-time dependencies.
-        return Vec::new();
-    }
-
-    if preferred_linkage == Linkage::Static {
-        // Attempt static linkage first. For dylibs and executables, we may be
-        // able to retry below with dynamic linkage.
-        if let Some(v) = attempt_static(tcx) {
-            return v;
-        }
-
-        // Staticlibs and static executables must have all static dependencies.
-        // If any are not found, generate some nice pretty errors.
-        if ty == CrateType::Staticlib
-            || (ty == CrateType::Executable
-                && sess.crt_static(Some(ty))
-                && !sess.target.crt_static_allows_dylibs)
-        {
-            for &cnum in tcx.crates(()).iter() {
-                if tcx.dep_kind(cnum).macros_only() {
-                    continue;
-                }
-                let src = tcx.used_crate_source(cnum);
-                if src.rlib.is_some() {
-                    continue;
-                }
-                sess.emit_err(RlibRequired { crate_name: tcx.crate_name(cnum) });
+        Linkage::NotLinked => return Vec::new(),
+        Linkage::Static => {
+            // Attempt static linkage first. For dylibs and executables, we may be
+            // able to retry below with dynamic linkage.
+            if let Some(v) = attempt_static(tcx) {
+                return v;
+            }
+
+            // Staticlibs and static executables must have all static dependencies.
+            // If any are not found, generate some nice pretty errors.
+            if ty == CrateType::Staticlib
+                || (ty == CrateType::Executable
+                    && sess.crt_static(Some(ty))
+                    && !sess.target.crt_static_allows_dylibs)
+            {
+                for &cnum in tcx.crates(()).iter() {
+                    if tcx.dep_kind(cnum).macros_only() {
+                        continue;
+                    }
+                    let src = tcx.used_crate_source(cnum);
+                    if src.rlib.is_some() {
+                        continue;
+                    }
+                    sess.emit_err(RlibRequired { crate_name: tcx.crate_name(cnum) });
+                }
+                return Vec::new();
             }
-            return Vec::new();
         }
+        Linkage::Dynamic | Linkage::IncludedFromDylib => {}
     }
 
     let mut formats = FxHashMap::default();
@@ -283,12 +283,9 @@ fn attempt_static(tcx: TyCtxt<'_>) -> Option<DependencyList> {
     let mut ret = tcx
         .crates(())
         .iter()
-        .map(|&cnum| {
-            if tcx.dep_kind(cnum) == CrateDepKind::Explicit {
-                Linkage::Static
-            } else {
-                Linkage::NotLinked
-            }
+        .map(|&cnum| match tcx.dep_kind(cnum) {
+            CrateDepKind::Explicit => Linkage::Static,
+            CrateDepKind::MacrosOnly | CrateDepKind::Implicit => Linkage::NotLinked,
         })
         .collect::<Vec<_>>();
 

compiler/rustc_metadata/src/native_libs.rs

@@ -107,7 +107,7 @@ impl<'tcx> Collector<'tcx> {
             return;
         };
 
-        if abi == Abi::Rust || abi == Abi::RustIntrinsic || abi == Abi::PlatformIntrinsic {
+        if matches!(abi, Abi::Rust | Abi::RustIntrinsic | Abi::PlatformIntrinsic) {
             return;
         }
 

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1415,7 +1415,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             if encode_opt {
                 record!(self.tables.optimized_mir[def_id.to_def_id()] <- tcx.optimized_mir(def_id));
 
-                if let DefKind::Generator = self.tcx.def_kind(def_id) && tcx.sess.opts.unstable_opts.drop_tracking_mir {
+                if tcx.sess.opts.unstable_opts.drop_tracking_mir && let DefKind::Generator = self.tcx.def_kind(def_id) {
                     record!(self.tables.mir_generator_witnesses[def_id.to_def_id()] <- tcx.mir_generator_witnesses(def_id));
                 }
             }

compiler/rustc_middle/src/hir/map/mod.rs

@@ -290,7 +290,7 @@ impl<'hir> Map<'hir> {
     #[track_caller]
     pub fn parent_id(self, hir_id: HirId) -> HirId {
         self.opt_parent_id(hir_id)
-            .unwrap_or_else(|| bug!("No parent for node {:?}", self.node_to_string(hir_id)))
+            .unwrap_or_else(|| bug!("No parent for node {}", self.node_to_string(hir_id)))
     }
 
     pub fn get_parent(self, hir_id: HirId) -> Node<'hir> {
@@ -1191,12 +1191,10 @@ fn upstream_crates(tcx: TyCtxt<'_>) -> Vec<(StableCrateId, Svh)> {
 }
 
 fn hir_id_to_string(map: Map<'_>, id: HirId) -> String {
-    let id_str = format!(" (hir_id={})", id);
-
     let path_str = |def_id: LocalDefId| map.tcx.def_path_str(def_id.to_def_id());
 
     let span_str = || map.tcx.sess.source_map().span_to_snippet(map.span(id)).unwrap_or_default();
-    let node_str = |prefix| format!("{} {}{}", prefix, span_str(), id_str);
+    let node_str = |prefix| format!("{id} ({prefix} `{}`)", span_str());
 
     match map.find(id) {
         Some(Node::Item(item)) => {
@@ -1225,10 +1223,10 @@ fn hir_id_to_string(map: Map<'_>, id: HirId) -> String {
                 ItemKind::TraitAlias(..) => "trait alias",
                 ItemKind::Impl { .. } => "impl",
             };
-            format!("{} {}{}", item_str, path_str(item.owner_id.def_id), id_str)
+            format!("{id} ({item_str} {})", path_str(item.owner_id.def_id))
         }
         Some(Node::ForeignItem(item)) => {
-            format!("foreign item {}{}", path_str(item.owner_id.def_id), id_str)
+            format!("{id} (foreign item {})", path_str(item.owner_id.def_id))
         }
         Some(Node::ImplItem(ii)) => {
             let kind = match ii.kind {
@@ -1236,7 +1234,7 @@ fn hir_id_to_string(map: Map<'_>, id: HirId) -> String {
                 ImplItemKind::Fn(..) => "method",
                 ImplItemKind::Type(_) => "assoc type",
             };
-            format!("{} {} in {}{}", kind, ii.ident, path_str(ii.owner_id.def_id), id_str)
+            format!("{id} ({kind} `{}` in {})", ii.ident, path_str(ii.owner_id.def_id))
         }
         Some(Node::TraitItem(ti)) => {
             let kind = match ti.kind {
@@ -1245,13 +1243,13 @@ fn hir_id_to_string(map: Map<'_>, id: HirId) -> String {
                 TraitItemKind::Type(..) => "assoc type",
             };
 
-            format!("{} {} in {}{}", kind, ti.ident, path_str(ti.owner_id.def_id), id_str)
+            format!("{id} ({kind} `{}` in {})", ti.ident, path_str(ti.owner_id.def_id))
         }
         Some(Node::Variant(ref variant)) => {
-            format!("variant {} in {}{}", variant.ident, path_str(variant.def_id), id_str)
+            format!("{id} (variant `{}` in {})", variant.ident, path_str(variant.def_id))
         }
         Some(Node::Field(ref field)) => {
-            format!("field {} in {}{}", field.ident, path_str(field.def_id), id_str)
+            format!("{id} (field `{}` in {})", field.ident, path_str(field.def_id))
         }
         Some(Node::AnonConst(_)) => node_str("const"),
         Some(Node::Expr(_)) => node_str("expr"),
@@ -1269,16 +1267,15 @@ fn hir_id_to_string(map: Map<'_>, id: HirId) -> String {
         Some(Node::Infer(_)) => node_str("infer"),
         Some(Node::Local(_)) => node_str("local"),
         Some(Node::Ctor(ctor)) => format!(
-            "ctor {}{}",
+            "{id} (ctor {})",
             ctor.ctor_def_id().map_or("<missing path>".into(), |def_id| path_str(def_id)),
-            id_str
         ),
         Some(Node::Lifetime(_)) => node_str("lifetime"),
         Some(Node::GenericParam(ref param)) => {
-            format!("generic_param {}{}", path_str(param.def_id), id_str)
+            format!("{id} (generic_param {})", path_str(param.def_id))
         }
-        Some(Node::Crate(..)) => String::from("root_crate"),
-        None => format!("unknown node{}", id_str),
+        Some(Node::Crate(..)) => String::from("(root_crate)"),
+        None => format!("{id} (unknown node)"),
     }
 }
 

compiler/rustc_middle/src/mir/coverage.rs

@@ -135,7 +135,10 @@ impl Debug for CoverageKind {
                 "Expression({:?}) = {} {} {}",
                 id.index(),
                 lhs.index(),
-                if *op == Op::Add { "+" } else { "-" },
+                match op {
+                    Op::Add => "+",
+                    Op::Subtract => "-",
+                },
                 rhs.index(),
             ),
             Unreachable => write!(fmt, "Unreachable"),

compiler/rustc_middle/src/mir/graphviz.rs

@@ -110,7 +110,7 @@ fn write_graph_label<'tcx, W: std::fmt::Write>(
         let decl = &body.local_decls[local];
 
         write!(w, "let ")?;
-        if decl.mutability == Mutability::Mut {
+        if decl.mutability.is_mut() {
             write!(w, "mut ")?;
         }
 

compiler/rustc_middle/src/mir/mod.rs

@@ -416,11 +416,7 @@ impl<'tcx> Body<'tcx> {
         (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
             let local = Local::new(index);
             let decl = &self.local_decls[local];
-            if decl.is_user_variable() && decl.mutability == Mutability::Mut {
-                Some(local)
-            } else {
-                None
-            }
+            (decl.is_user_variable() && decl.mutability.is_mut()).then(|| local)
         })
     }
 

compiler/rustc_middle/src/mir/pretty.rs

@@ -580,7 +580,7 @@ fn write_scope_tree(
             continue;
         }
 
-        let mut_str = if local_decl.mutability == Mutability::Mut { "mut " } else { "" };
+        let mut_str = local_decl.mutability.prefix_str();
 
         let mut indented_decl =
             format!("{0:1$}let {2}{3:?}: {4:?}", INDENT, indent, mut_str, local, local_decl.ty);

compiler/rustc_middle/src/ty/context.rs

@@ -2171,7 +2171,7 @@ impl<'tcx> TyCtxt<'tcx> {
             self.late_bound_vars_map(id.owner)
                 .and_then(|map| map.get(&id.local_id).cloned())
                 .unwrap_or_else(|| {
-                    bug!("No bound vars found for {:?} ({:?})", self.hir().node_to_string(id), id)
+                    bug!("No bound vars found for {}", self.hir().node_to_string(id))
                 })
                 .iter(),
         )

compiler/rustc_middle/src/ty/error.rs

@@ -8,9 +8,7 @@ use rustc_span::symbol::Symbol;
 use rustc_target::spec::abi;
 use std::borrow::Cow;
 use std::collections::hash_map::DefaultHasher;
-use std::fmt;
-use std::hash::Hash;
-use std::hash::Hasher;
+use std::hash::{Hash, Hasher};
 use std::path::PathBuf;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, TypeFoldable, TypeVisitable, Lift)]
@@ -30,7 +28,7 @@ impl<T> ExpectedFound<T> {
 }
 
 // Data structures used in type unification
-#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift, PartialEq, Eq)]
 #[rustc_pass_by_value]
 pub enum TypeError<'tcx> {
     Mismatch,
@@ -87,20 +85,16 @@ impl TypeError<'_> {
 /// in parentheses after some larger message. You should also invoke `note_and_explain_type_err()`
 /// afterwards to present additional details, particularly when it comes to lifetime-related
 /// errors.
-impl<'tcx> fmt::Display for TypeError<'tcx> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+impl<'tcx> TypeError<'tcx> {
+    pub fn to_string(self, tcx: TyCtxt<'tcx>) -> Cow<'static, str> {
         use self::TypeError::*;
-        fn report_maybe_different(
-            f: &mut fmt::Formatter<'_>,
-            expected: &str,
-            found: &str,
-        ) -> fmt::Result {
+        fn report_maybe_different(expected: &str, found: &str) -> String {
             // A naive approach to making sure that we're not reporting silly errors such as:
             // (expected closure, found closure).
             if expected == found {
-                write!(f, "expected {}, found a different {}", expected, found)
+                format!("expected {}, found a different {}", expected, found)
             } else {
-                write!(f, "expected {}, found {}", expected, found)
+                format!("expected {}, found {}", expected, found)
             }
         }
 
@@ -109,64 +103,63 @@ impl<'tcx> fmt::Display for TypeError<'tcx> {
             _ => String::new(),
         };
 
-        match *self {
-            CyclicTy(_) => write!(f, "cyclic type of infinite size"),
-            CyclicConst(_) => write!(f, "encountered a self-referencing constant"),
-            Mismatch => write!(f, "types differ"),
+        match self {
+            CyclicTy(_) => "cyclic type of infinite size".into(),
+            CyclicConst(_) => "encountered a self-referencing constant".into(),
+            Mismatch => "types differ".into(),
             ConstnessMismatch(values) => {
-                write!(f, "expected {} bound, found {} bound", values.expected, values.found)
+                format!("expected {} bound, found {} bound", values.expected, values.found).into()
             }
             PolarityMismatch(values) => {
-                write!(f, "expected {} polarity, found {} polarity", values.expected, values.found)
+                format!("expected {} polarity, found {} polarity", values.expected, values.found)
+                    .into()
             }
             UnsafetyMismatch(values) => {
-                write!(f, "expected {} fn, found {} fn", values.expected, values.found)
+                format!("expected {} fn, found {} fn", values.expected, values.found).into()
             }
             AbiMismatch(values) => {
-                write!(f, "expected {} fn, found {} fn", values.expected, values.found)
+                format!("expected {} fn, found {} fn", values.expected, values.found).into()
             }
-            ArgumentMutability(_) | Mutability => write!(f, "types differ in mutability"),
-            TupleSize(values) => write!(
-                f,
+            ArgumentMutability(_) | Mutability => "types differ in mutability".into(),
+            TupleSize(values) => format!(
                 "expected a tuple with {} element{}, found one with {} element{}",
                 values.expected,
                 pluralize!(values.expected),
                 values.found,
                 pluralize!(values.found)
-            ),
-            FixedArraySize(values) => write!(
-                f,
+            )
+            .into(),
+            FixedArraySize(values) => format!(
                 "expected an array with a fixed size of {} element{}, found one with {} element{}",
                 values.expected,
                 pluralize!(values.expected),
                 values.found,
                 pluralize!(values.found)
-            ),
-            ArgCount => write!(f, "incorrect number of function parameters"),
-            FieldMisMatch(adt, field) => write!(f, "field type mismatch: {}.{}", adt, field),
-            RegionsDoesNotOutlive(..) => write!(f, "lifetime mismatch"),
+            )
+            .into(),
+            ArgCount => "incorrect number of function parameters".into(),
+            FieldMisMatch(adt, field) => format!("field type mismatch: {}.{}", adt, field).into(),
+            RegionsDoesNotOutlive(..) => "lifetime mismatch".into(),
             // Actually naming the region here is a bit confusing because context is lacking
             RegionsInsufficientlyPolymorphic(..) => {
-                write!(f, "one type is more general than the other")
+                "one type is more general than the other".into()
             }
-            RegionsOverlyPolymorphic(br, _) => write!(
-                f,
+            RegionsOverlyPolymorphic(br, _) => format!(
                 "expected concrete lifetime, found bound lifetime parameter{}",
                 br_string(br)
-            ),
-            RegionsPlaceholderMismatch => write!(f, "one type is more general than the other"),
-            ArgumentSorts(values, _) | Sorts(values) => ty::tls::with(|tcx| {
-                let (mut expected, mut found) = with_forced_trimmed_paths!((
-                    values.expected.sort_string(tcx),
-                    values.found.sort_string(tcx),
-                ));
+            )
+            .into(),
+            RegionsPlaceholderMismatch => "one type is more general than the other".into(),
+            ArgumentSorts(values, _) | Sorts(values) => {
+                let mut expected = values.expected.sort_string(tcx);
+                let mut found = values.found.sort_string(tcx);
                 if expected == found {
                     expected = values.expected.sort_string(tcx);
                     found = values.found.sort_string(tcx);
                 }
-                report_maybe_different(f, &expected, &found)
-            }),
-            Traits(values) => ty::tls::with(|tcx| {
+                report_maybe_different(&expected, &found).into()
+            }
+            Traits(values) => {
                 let (mut expected, mut found) = with_forced_trimmed_paths!((
                     tcx.def_path_str(values.expected),
                     tcx.def_path_str(values.found),
@@ -175,12 +168,9 @@ impl<'tcx> fmt::Display for TypeError<'tcx> {
                     expected = tcx.def_path_str(values.expected);
                     found = tcx.def_path_str(values.found);
                 }
-                report_maybe_different(
-                    f,
-                    &format!("trait `{expected}`"),
-                    &format!("trait `{found}`"),
-                )
-            }),
+                report_maybe_different(&format!("trait `{expected}`"), &format!("trait `{found}`"))
+                    .into()
+            }
             IntMismatch(ref values) => {
                 let expected = match values.expected {
                     ty::IntVarValue::IntType(ty) => ty.name_str(),
@@ -190,43 +180,38 @@ impl<'tcx> fmt::Display for TypeError<'tcx> {
                     ty::IntVarValue::IntType(ty) => ty.name_str(),
                     ty::IntVarValue::UintType(ty) => ty.name_str(),
                 };
-                write!(f, "expected `{}`, found `{}`", expected, found)
+                format!("expected `{}`, found `{}`", expected, found).into()
             }
-            FloatMismatch(ref values) => {
-                write!(
-                    f,
-                    "expected `{}`, found `{}`",
-                    values.expected.name_str(),
-                    values.found.name_str()
-                )
-            }
-            VariadicMismatch(ref values) => write!(
-                f,
+            FloatMismatch(ref values) => format!(
+                "expected `{}`, found `{}`",
+                values.expected.name_str(),
+                values.found.name_str()
+            )
+            .into(),
+            VariadicMismatch(ref values) => format!(
                 "expected {} fn, found {} function",
                 if values.expected { "variadic" } else { "non-variadic" },
                 if values.found { "variadic" } else { "non-variadic" }
-            ),
-            ProjectionMismatched(ref values) => ty::tls::with(|tcx| {
-                write!(
-                    f,
-                    "expected {}, found {}",
-                    tcx.def_path_str(values.expected),
-                    tcx.def_path_str(values.found)
-                )
-            }),
+            )
+            .into(),
+            ProjectionMismatched(ref values) => format!(
+                "expected `{}`, found `{}`",
+                tcx.def_path_str(values.expected),
+                tcx.def_path_str(values.found)
+            )
+            .into(),
             ExistentialMismatch(ref values) => report_maybe_different(
-                f,
                 &format!("trait `{}`", values.expected),
                 &format!("trait `{}`", values.found),
-            ),
+            )
+            .into(),
             ConstMismatch(ref values) => {
-                write!(f, "expected `{}`, found `{}`", values.expected, values.found)
+                format!("expected `{}`, found `{}`", values.expected, values.found).into()
+            }
+            IntrinsicCast => "cannot coerce intrinsics to function pointers".into(),
+            TargetFeatureCast(_) => {
+                "cannot coerce functions with `#[target_feature]` to safe function pointers".into()
             }
-            IntrinsicCast => write!(f, "cannot coerce intrinsics to function pointers"),
-            TargetFeatureCast(_) => write!(
-                f,
-                "cannot coerce functions with `#[target_feature]` to safe function pointers"
-            ),
         }
     }
 }
@@ -259,60 +244,9 @@ impl<'tcx> TypeError<'tcx> {
 }
 
 impl<'tcx> Ty<'tcx> {
-    pub fn sort_string(self, tcx: TyCtxt<'_>) -> Cow<'static, str> {
+    pub fn sort_string(self, tcx: TyCtxt<'tcx>) -> Cow<'static, str> {
         match *self.kind() {
-            ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Str | ty::Never => {
-                format!("`{}`", self).into()
-            }
-            ty::Tuple(ref tys) if tys.is_empty() => format!("`{}`", self).into(),
-
-            ty::Adt(def, _) => format!("{} `{}`", def.descr(), tcx.def_path_str(def.did())).into(),
             ty::Foreign(def_id) => format!("extern type `{}`", tcx.def_path_str(def_id)).into(),
-            ty::Array(t, n) => {
-                if t.is_simple_ty() {
-                    return format!("array `{}`", self).into();
-                }
-
-                let n = tcx.lift(n).unwrap();
-                if let ty::ConstKind::Value(v) = n.kind() {
-                    if let Some(n) = v.try_to_machine_usize(tcx) {
-                        return format!("array of {} element{}", n, pluralize!(n)).into();
-                    }
-                }
-                "array".into()
-            }
-            ty::Slice(ty) if ty.is_simple_ty() => format!("slice `{}`", self).into(),
-            ty::Slice(_) => "slice".into(),
-            ty::RawPtr(tymut) => {
-                let tymut_string = match tymut.mutbl {
-                    hir::Mutability::Mut => tymut.to_string(),
-                    hir::Mutability::Not => format!("const {}", tymut.ty),
-                };
-
-                if tymut_string != "_" && (tymut.ty.is_simple_text() || tymut_string.len() < "const raw pointer".len()) {
-                    format!("`*{}`", tymut_string).into()
-                } else {
-                    // Unknown type name, it's long or has type arguments
-                    "raw pointer".into()
-                }
-            },
-            ty::Ref(_, ty, mutbl) => {
-                let tymut = ty::TypeAndMut { ty, mutbl };
-                let tymut_string = tymut.to_string();
-
-                if tymut_string != "_"
-                    && (ty.is_simple_text() || tymut_string.len() < "mutable reference".len())
-                {
-                    format!("`&{}`", tymut_string).into()
-                } else {
-                    // Unknown type name, it's long or has type arguments
-                    match mutbl {
-                        hir::Mutability::Mut => "mutable reference",
-                        _ => "reference",
-                    }
-                    .into()
-                }
-            }
             ty::FnDef(def_id, ..) => match tcx.def_kind(def_id) {
                 DefKind::Ctor(CtorOf::Struct, _) => "struct constructor".into(),
                 DefKind::Ctor(CtorOf::Variant, _) => "enum constructor".into(),
@@ -320,14 +254,13 @@ impl<'tcx> Ty<'tcx> {
             },
             ty::FnPtr(_) => "fn pointer".into(),
             ty::Dynamic(ref inner, ..) if let Some(principal) = inner.principal() => {
-                format!("trait object `dyn {}`", tcx.def_path_str(principal.def_id())).into()
+                format!("`dyn {}`", tcx.def_path_str(principal.def_id())).into()
             }
             ty::Dynamic(..) => "trait object".into(),
             ty::Closure(..) => "closure".into(),
             ty::Generator(def_id, ..) => tcx.generator_kind(def_id).unwrap().descr().into(),
             ty::GeneratorWitness(..) |
             ty::GeneratorWitnessMIR(..) => "generator witness".into(),
-            ty::Tuple(..) => "tuple".into(),
             ty::Infer(ty::TyVar(_)) => "inferred type".into(),
             ty::Infer(ty::IntVar(_)) => "integer".into(),
             ty::Infer(ty::FloatVar(_)) => "floating-point number".into(),
@@ -337,9 +270,14 @@ impl<'tcx> Ty<'tcx> {
             ty::Infer(ty::FreshIntTy(_)) => "fresh integral type".into(),
             ty::Infer(ty::FreshFloatTy(_)) => "fresh floating-point type".into(),
             ty::Alias(ty::Projection, _) => "associated type".into(),
-            ty::Param(p) => format!("type parameter `{}`", p).into(),
+            ty::Param(p) => format!("type parameter `{p}`").into(),
             ty::Alias(ty::Opaque, ..) => "opaque type".into(),
             ty::Error(_) => "type error".into(),
+            _ => {
+                let width = tcx.sess.diagnostic_width();
+                let length_limit = std::cmp::max(width / 4, 15);
+                format!("`{}`", tcx.ty_string_with_limit(self, length_limit)).into()
+            }
         }
     }
 
@@ -386,16 +324,14 @@ impl<'tcx> Ty<'tcx> {
 }
 
 impl<'tcx> TyCtxt<'tcx> {
-    pub fn short_ty_string(self, ty: Ty<'tcx>) -> (String, Option<PathBuf>) {
-        let width = self.sess.diagnostic_width();
-        let length_limit = width.saturating_sub(30);
+    pub fn ty_string_with_limit(self, ty: Ty<'tcx>, length_limit: usize) -> String {
         let mut type_limit = 50;
         let regular = FmtPrinter::new(self, hir::def::Namespace::TypeNS)
             .pretty_print_type(ty)
             .expect("could not write to `String`")
             .into_buffer();
-        if regular.len() <= width {
-            return (regular, None);
+        if regular.len() <= length_limit {
+            return regular;
         }
         let mut short;
         loop {
@@ -415,6 +351,20 @@ impl<'tcx> TyCtxt<'tcx> {
             }
             type_limit -= 1;
         }
+        short
+    }
+
+    pub fn short_ty_string(self, ty: Ty<'tcx>) -> (String, Option<PathBuf>) {
+        let width = self.sess.diagnostic_width();
+        let length_limit = width.saturating_sub(30);
+        let regular = FmtPrinter::new(self, hir::def::Namespace::TypeNS)
+            .pretty_print_type(ty)
+            .expect("could not write to `String`")
+            .into_buffer();
+        if regular.len() <= width {
+            return (regular, None);
+        }
+        let short = self.ty_string_with_limit(ty, length_limit);
         if regular == short {
             return (regular, None);
         }

compiler/rustc_middle/src/ty/fold.rs

@@ -610,7 +610,9 @@ impl<'tcx> TyCtxt<'tcx> {
                 let index = entry.index();
                 let var = ty::BoundVar::from_usize(index);
                 let kind = entry
-                    .or_insert_with(|| ty::BoundVariableKind::Ty(ty::BoundTyKind::Anon))
+                    .or_insert_with(|| {
+                        ty::BoundVariableKind::Ty(ty::BoundTyKind::Anon(index as u32))
+                    })
                     .expect_ty();
                 self.tcx.mk_ty(ty::Bound(ty::INNERMOST, BoundTy { var, kind }))
             }

compiler/rustc_middle/src/ty/mod.rs

@@ -1369,7 +1369,7 @@ pub struct Placeholder<T> {
 
 pub type PlaceholderRegion = Placeholder<BoundRegionKind>;
 
-pub type PlaceholderType = Placeholder<BoundVar>;
+pub type PlaceholderType = Placeholder<BoundTyKind>;
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
 #[derive(TyEncodable, TyDecodable, PartialOrd, Ord)]

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -698,8 +698,10 @@ pub trait PrettyPrinter<'tcx>:
             ty::Error(_) => p!("[type error]"),
             ty::Param(ref param_ty) => p!(print(param_ty)),
             ty::Bound(debruijn, bound_ty) => match bound_ty.kind {
-                ty::BoundTyKind::Anon => self.pretty_print_bound_var(debruijn, bound_ty.var)?,
-                ty::BoundTyKind::Param(p) => p!(write("{}", p)),
+                ty::BoundTyKind::Anon(bv) => {
+                    self.pretty_print_bound_var(debruijn, ty::BoundVar::from_u32(bv))?
+                }
+                ty::BoundTyKind::Param(_, s) => p!(write("{}", s)),
             },
             ty::Adt(def, substs) => {
                 p!(print_def_path(def.did(), substs));
@@ -1084,9 +1086,11 @@ pub trait PrettyPrinter<'tcx>:
             write!(self, "Sized")?;
         }
 
-        for re in lifetimes {
-            write!(self, " + ")?;
-            self = self.print_region(re)?;
+        if !FORCE_TRIMMED_PATH.with(|flag| flag.get()) {
+            for re in lifetimes {
+                write!(self, " + ")?;
+                self = self.print_region(re)?;
+            }
         }
 
         Ok(self)
@@ -2070,6 +2074,10 @@ impl<'tcx> PrettyPrinter<'tcx> for FmtPrinter<'_, 'tcx> {
             return true;
         }
 
+        if FORCE_TRIMMED_PATH.with(|flag| flag.get()) {
+            return false;
+        }
+
         let identify_regions = self.tcx.sess.opts.unstable_opts.identify_regions;
 
         match *region {
@@ -2346,6 +2354,7 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
         } else {
             let tcx = self.tcx;
 
+            let trim_path = FORCE_TRIMMED_PATH.with(|flag| flag.get());
             // Closure used in `RegionFolder` to create names for anonymous late-bound
             // regions. We use two `DebruijnIndex`es (one for the currently folded
             // late-bound region and the other for the binder level) to determine
@@ -2400,8 +2409,10 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
                     }
                 };
 
-                start_or_continue(&mut self, "for<", ", ");
-                do_continue(&mut self, name);
+                if !trim_path {
+                    start_or_continue(&mut self, "for<", ", ");
+                    do_continue(&mut self, name);
+                }
                 tcx.mk_region(ty::ReLateBound(ty::INNERMOST, ty::BoundRegion { var: br.var, kind }))
             };
             let mut folder = RegionFolder {
@@ -2412,7 +2423,9 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
             };
             let new_value = value.clone().skip_binder().fold_with(&mut folder);
             let region_map = folder.region_map;
-            start_or_continue(&mut self, "", "> ");
+            if !trim_path {
+                start_or_continue(&mut self, "", "> ");
+            }
             (new_value, region_map)
         };
 

compiler/rustc_middle/src/ty/structural_impls.rs

@@ -240,6 +240,7 @@ TrivialTypeTraversalAndLiftImpls! {
     crate::ty::AssocKind,
     crate::ty::AliasKind,
     crate::ty::Placeholder<crate::ty::BoundRegionKind>,
+    crate::ty::Placeholder<crate::ty::BoundTyKind>,
     crate::ty::ClosureKind,
     crate::ty::FreeRegion,
     crate::ty::InferTy,

compiler/rustc_middle/src/ty/sty.rs

@@ -1504,13 +1504,22 @@ pub struct BoundTy {
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
 #[derive(HashStable)]
 pub enum BoundTyKind {
-    Anon,
-    Param(Symbol),
+    Anon(u32),
+    Param(DefId, Symbol),
+}
+
+impl BoundTyKind {
+    pub fn expect_anon(self) -> u32 {
+        match self {
+            BoundTyKind::Anon(i) => i,
+            _ => bug!(),
+        }
+    }
 }
 
 impl From<BoundVar> for BoundTy {
     fn from(var: BoundVar) -> Self {
-        BoundTy { var, kind: BoundTyKind::Anon }
+        BoundTy { var, kind: BoundTyKind::Anon(var.as_u32()) }
     }
 }
 

compiler/rustc_middle/src/ty/typeck_results.rs

@@ -372,7 +372,7 @@ impl<'tcx> TypeckResults<'tcx> {
 
     pub fn node_type(&self, id: hir::HirId) -> Ty<'tcx> {
         self.node_type_opt(id).unwrap_or_else(|| {
-            bug!("node_type: no type for node `{}`", tls::with(|tcx| tcx.hir().node_to_string(id)))
+            bug!("node_type: no type for node {}", tls::with(|tcx| tcx.hir().node_to_string(id)))
         })
     }
 
@@ -551,9 +551,8 @@ fn validate_hir_id_for_typeck_results(hir_owner: OwnerId, hir_id: hir::HirId) {
 fn invalid_hir_id_for_typeck_results(hir_owner: OwnerId, hir_id: hir::HirId) {
     ty::tls::with(|tcx| {
         bug!(
-            "node {} with HirId::owner {:?} cannot be placed in TypeckResults with hir_owner {:?}",
+            "node {} cannot be placed in TypeckResults with hir_owner {:?}",
             tcx.hir().node_to_string(hir_id),
-            hir_id.owner,
             hir_owner
         )
     });

compiler/rustc_mir_build/src/build/expr/as_temp.rs

@@ -44,7 +44,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let expr_ty = expr.ty;
         let temp = {
             let mut local_decl = LocalDecl::new(expr_ty, expr_span);
-            if mutability == Mutability::Not {
+            if mutability.is_not() {
                 local_decl = local_decl.immutable();
             }
 

compiler/rustc_mir_transform/src/check_packed_ref.rs

@@ -1,7 +1,7 @@
+use rustc_errors::struct_span_err;
 use rustc_middle::mir::visit::{PlaceContext, Visitor};
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, TyCtxt};
-use rustc_session::lint::builtin::UNALIGNED_REFERENCES;
 
 use crate::util;
 use crate::MirLint;
@@ -49,31 +49,22 @@ impl<'tcx> Visitor<'tcx> for PackedRefChecker<'_, 'tcx> {
                     // shouldn't do.
                     unreachable!();
                 } else {
-                    let source_info = self.source_info;
-                    let lint_root = self.body.source_scopes[source_info.scope]
-                        .local_data
-                        .as_ref()
-                        .assert_crate_local()
-                        .lint_root;
-                    self.tcx.struct_span_lint_hir(
-                        UNALIGNED_REFERENCES,
-                        lint_root,
-                        source_info.span,
-                        "reference to packed field is unaligned",
-                        |lint| {
-                            lint
-                                .note(
-                                    "fields of packed structs are not properly aligned, and creating \
-                                    a misaligned reference is undefined behavior (even if that \
-                                    reference is never dereferenced)",
-                                )
-                                .help(
-                                    "copy the field contents to a local variable, or replace the \
-                                    reference with a raw pointer and use `read_unaligned`/`write_unaligned` \
-                                    (loads and stores via `*p` must be properly aligned even when using raw pointers)"
-                                )
-                        },
-                    );
+                    struct_span_err!(
+                        self.tcx.sess,
+                        self.source_info.span,
+                        E0793,
+                        "reference to packed field is unaligned"
+                    )
+                    .note(
+                        "fields of packed structs are not properly aligned, and creating \
+                        a misaligned reference is undefined behavior (even if that \
+                        reference is never dereferenced)",
+                    ).help(
+                        "copy the field contents to a local variable, or replace the \
+                        reference with a raw pointer and use `read_unaligned`/`write_unaligned` \
+                        (loads and stores via `*p` must be properly aligned even when using raw pointers)"
+                    )
+                    .emit();
                 }
             }
         }

compiler/rustc_mir_transform/src/const_prop.rs

@@ -5,7 +5,6 @@ use std::cell::Cell;
 
 use either::Right;
 
-use rustc_ast::Mutability;
 use rustc_const_eval::const_eval::CheckAlignment;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def::DefKind;
@@ -289,7 +288,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine<'mir, 'tcx>
         }
         // If the static allocation is mutable, then we can't const prop it as its content
         // might be different at runtime.
-        if alloc.inner().mutability == Mutability::Mut {
+        if alloc.inner().mutability.is_mut() {
             throw_machine_stop_str!("can't access mutable globals in ConstProp");
         }
 
@@ -528,7 +527,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
         let r = self.use_ecx(|this| this.ecx.read_immediate(&this.ecx.eval_operand(right, None)?));
         let l = self.use_ecx(|this| this.ecx.read_immediate(&this.ecx.eval_operand(left, None)?));
         // Check for exceeding shifts *even if* we cannot evaluate the LHS.
-        if op == BinOp::Shr || op == BinOp::Shl {
+        if matches!(op, BinOp::Shr | BinOp::Shl) {
             let r = r.clone()?;
             // We need the type of the LHS. We cannot use `place_layout` as that is the type
             // of the result, which for checked binops is not the same!

compiler/rustc_mir_transform/src/const_prop_lint.rs

@@ -368,7 +368,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             this.ecx.read_immediate(&this.ecx.eval_operand(left, None)?)
         });
         // Check for exceeding shifts *even if* we cannot evaluate the LHS.
-        if op == BinOp::Shr || op == BinOp::Shl {
+        if matches!(op, BinOp::Shr | BinOp::Shl) {
             let r = r.clone()?;
             // We need the type of the LHS. We cannot use `place_layout` as that is the type
             // of the result, which for checked binops is not the same!