Rename DiagnosticBuilder as Diag.

Much better!

Note that this involves renaming (and updating the value of)
`DIAGNOSTIC_BUILDER` in clippy.

src/librustdoc/doctest.rs

@@ -643,8 +643,8 @@ pub(crate) fn make_test(
 
             // Reset errors so that they won't be reported as compiler bugs when dropping the
             // dcx. Any errors in the tests will be reported when the test file is compiled,
-            // Note that we still need to cancel the errors above otherwise `DiagnosticBuilder`
-            // will panic on drop.
+            // Note that we still need to cancel the errors above otherwise `Diag` will panic on
+            // drop.
             sess.dcx.reset_err_count();
 
             (found_main, found_extern_crate, found_macro)

src/librustdoc/html/markdown.rs

@@ -27,7 +27,7 @@
 //! ```
 
 use rustc_data_structures::fx::FxHashMap;
-use rustc_errors::{DiagnosticBuilder, DiagnosticMessage};
+use rustc_errors::{Diag, DiagnosticMessage};
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::TyCtxt;
 pub(crate) use rustc_resolve::rustdoc::main_body_opts;
@@ -843,7 +843,7 @@ impl<'tcx> ExtraInfo<'tcx> {
     fn error_invalid_codeblock_attr_with_help(
         &self,
         msg: impl Into<DiagnosticMessage>,
-        f: impl for<'a, 'b> FnOnce(&'b mut DiagnosticBuilder<'a, ()>),
+        f: impl for<'a, 'b> FnOnce(&'b mut Diag<'a, ()>),
     ) {
         if let Some(def_id) = self.def_id.as_local() {
             self.tcx.node_span_lint(

src/librustdoc/passes/collect_intra_doc_links.rs

@@ -8,7 +8,7 @@ use rustc_data_structures::{
     fx::{FxHashMap, FxHashSet},
     intern::Interned,
 };
-use rustc_errors::{Applicability, DiagnosticBuilder, DiagnosticMessage};
+use rustc_errors::{Applicability, Diag, DiagnosticMessage};
 use rustc_hir::def::Namespace::*;
 use rustc_hir::def::{DefKind, Namespace, PerNS};
 use rustc_hir::def_id::{DefId, CRATE_DEF_ID};
@@ -1173,22 +1173,21 @@ impl LinkCollector<'_, '_> {
     ) {
         // The resolved item did not match the disambiguator; give a better error than 'not found'
         let msg = format!("incompatible link kind for `{path_str}`");
-        let callback =
-            |diag: &mut DiagnosticBuilder<'_, ()>, sp: Option<rustc_span::Span>, link_range| {
-                let note = format!(
-                    "this link resolved to {} {}, which is not {} {}",
-                    resolved.article(),
-                    resolved.descr(),
-                    specified.article(),
-                    specified.descr(),
-                );
-                if let Some(sp) = sp {
-                    diag.span_label(sp, note);
-                } else {
-                    diag.note(note);
-                }
-                suggest_disambiguator(resolved, diag, path_str, link_range, sp, diag_info);
-            };
+        let callback = |diag: &mut Diag<'_, ()>, sp: Option<rustc_span::Span>, link_range| {
+            let note = format!(
+                "this link resolved to {} {}, which is not {} {}",
+                resolved.article(),
+                resolved.descr(),
+                specified.article(),
+                specified.descr(),
+            );
+            if let Some(sp) = sp {
+                diag.span_label(sp, note);
+            } else {
+                diag.note(note);
+            }
+            suggest_disambiguator(resolved, diag, path_str, link_range, sp, diag_info);
+        };
         report_diagnostic(self.cx.tcx, BROKEN_INTRA_DOC_LINKS, msg, diag_info, callback);
     }
 
@@ -1677,7 +1676,7 @@ fn report_diagnostic(
     lint: &'static Lint,
     msg: impl Into<DiagnosticMessage> + Display,
     DiagnosticInfo { item, ori_link: _, dox, link_range }: &DiagnosticInfo<'_>,
-    decorate: impl FnOnce(&mut DiagnosticBuilder<'_, ()>, Option<rustc_span::Span>, MarkdownLinkRange),
+    decorate: impl FnOnce(&mut Diag<'_, ()>, Option<rustc_span::Span>, MarkdownLinkRange),
 ) {
     let Some(hir_id) = DocContext::as_local_hir_id(tcx, item.item_id) else {
         // If non-local, no need to check anything.
@@ -2125,7 +2124,7 @@ fn ambiguity_error(
 /// disambiguator.
 fn suggest_disambiguator(
     res: Res,
-    diag: &mut DiagnosticBuilder<'_, ()>,
+    diag: &mut Diag<'_, ()>,
     path_str: &str,
     link_range: MarkdownLinkRange,
     sp: Option<rustc_span::Span>,

src/librustdoc/passes/lint/unescaped_backticks.rs

@@ -4,7 +4,7 @@ use crate::clean::Item;
 use crate::core::DocContext;
 use crate::html::markdown::main_body_opts;
 use pulldown_cmark::{BrokenLink, Event, Parser};
-use rustc_errors::DiagnosticBuilder;
+use rustc_errors::Diag;
 use rustc_lint_defs::Applicability;
 use rustc_resolve::rustdoc::source_span_for_markdown_range;
 use std::ops::Range;
@@ -368,7 +368,7 @@ fn suggest_insertion(
     cx: &DocContext<'_>,
     item: &Item,
     dox: &str,
-    lint: &mut DiagnosticBuilder<'_, ()>,
+    lint: &mut Diag<'_, ()>,
     insert_index: usize,
     suggestion: char,
     message: &'static str,