Auto merge of #53053 - petrochenkov:custattr, r=alexcrichton

resolve:  Support custom attributes when macro modularization is enabled

Basically, if resolution of a single-segment attribute is a determined error, then we interpret it as a custom attribute.

Since custom attributes are integrated into general macro resolution, `feature(custom_attribute)` now requires and implicitly enables macro modularization (`feature(use_extern_macros)`).
Actually, a few other "advanced" macro features now implicitly enable macro modularization too (and one bug was found and fixed in process of enabling it).

The first two commits are preliminary cleanups/refactorings.

src/test/compile-fail-fulldeps/proc-macro/attr-invalid-exprs.rs

@@ -13,7 +13,7 @@
 
 //! Attributes producing expressions in invalid locations
 
-#![feature(use_extern_macros, stmt_expr_attributes, proc_macro_expr)]
+#![feature(stmt_expr_attributes, proc_macro_expr)]
 
 extern crate attr_stmt_expr;
 use attr_stmt_expr::{duplicate, no_output};

src/test/compile-fail-fulldeps/proc-macro/attr-stmt-expr.rs

@@ -11,7 +11,7 @@
 // aux-build:attr-stmt-expr.rs
 // ignore-stage1
 
-#![feature(use_extern_macros, proc_macro_expr)]
+#![feature(proc_macro_expr)]
 
 extern crate attr_stmt_expr;
 use attr_stmt_expr::{expect_let, expect_print_stmt, expect_expr, expect_print_expr};

src/test/compile-fail-fulldeps/proc-macro/issue-41211.rs

@@ -15,7 +15,7 @@
 
 #![feature(use_extern_macros)]
 #![emit_unchanged]
-//~^ ERROR: cannot find attribute macro `emit_unchanged` in this scope
+//~^ ERROR attribute `emit_unchanged` is currently unknown to the compiler
 extern crate issue_41211;
 use issue_41211::emit_unchanged;
 

src/test/compile-fail-fulldeps/proc-macro/issue-50493.rs

@@ -11,8 +11,6 @@
 // aux-build:issue_50493.rs
 // ignore-stage1
 
-#![feature(proc_macro)]
-
 #[macro_use]
 extern crate issue_50493;
 

src/test/compile-fail-fulldeps/proc-macro/lints_in_proc_macros.rs

@@ -11,7 +11,7 @@
 // aux-build:bang_proc_macro2.rs
 // ignore-stage1
 
-#![feature(use_extern_macros, proc_macro_non_items)]
+#![feature(proc_macro_non_items)]
 #![allow(unused_macros)]
 
 extern crate bang_proc_macro2;

src/test/compile-fail-fulldeps/proc-macro/macros-in-extern.rs

@@ -26,13 +26,13 @@ fn main() {
 #[link(name = "rust_test_helpers", kind = "static")]
 extern {
     #[no_output]
-    //~^ ERROR macro and proc-macro invocations in `extern {}` blocks are experimental.
+    //~^ ERROR macro invocations in `extern {}` blocks are experimental
     fn some_definitely_unknown_symbol_which_should_be_removed();
 
     #[nop_attr]
-    //~^ ERROR macro and proc-macro invocations in `extern {}` blocks are experimental.
+    //~^ ERROR macro invocations in `extern {}` blocks are experimental
     fn rust_get_test_int() -> isize;
 
     emit_input!(fn rust_dbg_extern_identity_u32(arg: u32) -> u32;);
-    //~^ ERROR macro and proc-macro invocations in `extern {}` blocks are experimental.
+    //~^ ERROR macro invocations in `extern {}` blocks are experimental
 }

src/test/compile-fail-fulldeps/proc-macro/proc-macro-gates.rs

@@ -16,7 +16,7 @@
 // gate-test-proc_macro_mod
 // gate-test-proc_macro_gen
 
-#![feature(use_extern_macros, stmt_expr_attributes)]
+#![feature(stmt_expr_attributes)]
 
 extern crate proc_macro_gates as foo;
 

src/test/compile-fail-fulldeps/proc-macro/proc-macro-gates2.rs

@@ -10,7 +10,7 @@
 
 // aux-build:proc-macro-gates.rs
 
-#![feature(use_extern_macros, stmt_expr_attributes)]
+#![feature(stmt_expr_attributes)]
 
 extern crate proc_macro_gates as foo;
 

src/test/compile-fail/macro-with-seps-err-msg.rs

@@ -10,10 +10,6 @@
 
 // gate-test-use_extern_macros
 
-#![feature(proc_macro_path_invoc)]
-
 fn main() {
     globnar::brotz!(); //~ ERROR non-ident macro paths are experimental
-    #[derive(foo::Bar)] struct T; //~ ERROR non-ident macro paths are experimental
-    ::foo!(); //~ ERROR non-ident macro paths are experimental
 }

src/test/compile-fail/macros-in-extern.rs

@@ -34,9 +34,9 @@ fn main() {
 #[link(name = "rust_test_helpers", kind = "static")]
 extern {
     returns_isize!(rust_get_test_int);
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental.
+    //~^ ERROR macro invocations in `extern {}` blocks are experimental
     takes_u32_returns_u32!(rust_dbg_extern_identity_u32);
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental.
+    //~^ ERROR macro invocations in `extern {}` blocks are experimental
     emits_nothing!();
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental.
+    //~^ ERROR macro invocations in `extern {}` blocks are experimental
 }

src/test/compile-fail/stmt_expr_attrs_no_feature.rs

@@ -20,7 +20,7 @@ fn main() {
     #[attr]
     fn a() {}
 
-    #[attr]
+    #[attr] //~ ERROR attributes on expressions are experimental
     {
 
     }

src/test/compile-fail/unknown-tool-name.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(use_extern_macros, proc_macro_path_invoc)]
+#![feature(proc_macro_path_invoc)]
 
 #[foo::bar] //~ ERROR failed to resolve. Use of undeclared type or module `foo`
 fn main() {}

src/test/pretty/attr-literals.rs

@@ -18,6 +18,6 @@ fn main() {
     #[align = 8]
     fn f() { }
 
-    #[vec(1, 2, 3)]
+    #[vector(1, 2, 3)]
     fn g() { }
 }

src/test/run-pass-fulldeps/auxiliary/cond_plugin.rs

@@ -11,7 +11,7 @@
 // no-prefer-dynamic
 
 #![crate_type = "proc-macro"]
-#![feature(proc_macro, proc_macro_non_items)]
+#![feature(proc_macro_non_items)]
 
 extern crate proc_macro;
 

src/test/run-pass-fulldeps/auxiliary/hello_macro.rs

@@ -11,7 +11,7 @@
 // no-prefer-dynamic
 
 #![crate_type = "proc-macro"]
-#![feature(use_extern_macros, proc_macro_non_items, proc_macro_quote)]
+#![feature(proc_macro_non_items, proc_macro_quote)]
 
 extern crate proc_macro;
 

src/test/run-pass-fulldeps/auxiliary/proc_macro_def.rs

@@ -11,7 +11,7 @@
 // no-prefer-dynamic
 
 #![crate_type = "proc-macro"]
-#![feature(proc_macro, proc_macro_non_items)]
+#![feature(proc_macro_non_items)]
 
 extern crate proc_macro;
 

src/test/run-pass-fulldeps/macro-quote-cond.rs

@@ -11,7 +11,7 @@
 // aux-build:cond_plugin.rs
 // ignore-stage1
 
-#![feature(use_extern_macros, proc_macro_non_items)]
+#![feature(proc_macro_non_items)]
 
 extern crate cond_plugin;
 

src/test/run-pass-fulldeps/macro-quote-test.rs

@@ -13,7 +13,7 @@
 // aux-build:hello_macro.rs
 // ignore-stage1
 
-#![feature(use_extern_macros, proc_macro_non_items, proc_macro_gen)]
+#![feature(proc_macro_non_items, proc_macro_gen)]
 
 extern crate hello_macro;
 

src/test/run-pass-fulldeps/proc-macro/attr-stmt-expr.rs

@@ -11,7 +11,7 @@
 // aux-build:attr-stmt-expr.rs
 // ignore-stage1
 
-#![feature(use_extern_macros, stmt_expr_attributes, proc_macro_expr)]
+#![feature(stmt_expr_attributes, proc_macro_expr)]
 
 extern crate attr_stmt_expr;
 use attr_stmt_expr::{expect_let, expect_print_stmt, expect_expr, expect_print_expr,

src/test/run-pass-fulldeps/proc-macro/auxiliary/count_compound_ops.rs

@@ -10,7 +10,7 @@
 
 // no-prefer-dynamic
 
-#![feature(proc_macro_non_items, proc_macro_quote, use_extern_macros)]
+#![feature(proc_macro_non_items, proc_macro_quote)]
 #![crate_type = "proc-macro"]
 
 extern crate proc_macro;

src/test/run-pass-fulldeps/proc-macro/auxiliary/hygiene_example_codegen.rs

@@ -10,7 +10,7 @@
 
 // no-prefer-dynamic
 
-#![feature(use_extern_macros, proc_macro_quote, proc_macro_non_items)]
+#![feature(proc_macro_quote, proc_macro_non_items)]
 #![crate_type = "proc-macro"]
 
 extern crate proc_macro as proc_macro_renamed; // This does not break `quote!`

src/test/run-pass-fulldeps/proc-macro/bang-macro.rs

@@ -11,7 +11,7 @@
 // aux-build:bang-macro.rs
 // ignore-stage1
 
-#![feature(use_extern_macros, proc_macro_non_items)]
+#![feature(proc_macro_non_items)]
 
 extern crate bang_macro;
 use bang_macro::rewrite;

src/test/run-pass-fulldeps/proc-macro/call-site.rs

@@ -11,7 +11,7 @@
 // aux-build:call-site.rs
 // ignore-stage1
 
-#![feature(proc_macro_non_items, use_extern_macros)]
+#![feature(proc_macro_non_items)]
 
 extern crate call_site;
 use call_site::*;

src/test/run-pass-fulldeps/proc-macro/count_compound_ops.rs

@@ -11,7 +11,7 @@
 // aux-build:count_compound_ops.rs
 // ignore-stage1
 
-#![feature(use_extern_macros, proc_macro_non_items)]
+#![feature(proc_macro_non_items)]
 
 extern crate count_compound_ops;
 use count_compound_ops::count_compound_ops;

src/test/run-pass-fulldeps/proc-macro/derive-b.rs

@@ -11,7 +11,7 @@
 // aux-build:derive-b.rs
 // ignore-stage1
 
-#![feature(use_extern_macros, proc_macro_path_invoc)]
+#![feature(proc_macro_path_invoc)]
 
 extern crate derive_b;
 

src/test/run-pass-fulldeps/proc-macro/hygiene_example.rs

@@ -12,7 +12,7 @@
 // aux-build:hygiene_example.rs
 // ignore-stage1
 
-#![feature(use_extern_macros, proc_macro_non_items)]
+#![feature(proc_macro_non_items)]
 
 extern crate hygiene_example;
 use hygiene_example::hello;

src/test/run-pass-fulldeps/proc-macro/macros-in-extern.rs

@@ -12,7 +12,7 @@
 // ignore-stage1
 // ignore-wasm32
 
-#![feature(use_extern_macros, macros_in_extern)]
+#![feature(macros_in_extern)]
 
 extern crate test_macros;
 

src/test/run-pass-fulldeps/proc_macro.rs

@@ -12,7 +12,7 @@
 // ignore-stage1
 // ignore-cross-compile
 
-#![feature(use_extern_macros, proc_macro_non_items)]
+#![feature(proc_macro_non_items)]
 
 extern crate proc_macro_def;
 

src/test/ui-fulldeps/auxiliary/attr_proc_macro.rs

@@ -10,7 +10,7 @@
 
 // force-host
 // no-prefer-dynamic
-#![feature(proc_macro)]
+
 #![crate_type = "proc-macro"]
 
 extern crate proc_macro;

src/test/ui-fulldeps/auxiliary/bang_proc_macro.rs

@@ -10,7 +10,7 @@
 
 // force-host
 // no-prefer-dynamic
-#![feature(proc_macro)]
+
 #![crate_type = "proc-macro"]
 
 extern crate proc_macro;

src/test/ui-fulldeps/auxiliary/lifetimes.rs

@@ -10,7 +10,6 @@
 
 // no-prefer-dynamic
 
-#![feature(proc_macro)]
 #![crate_type = "proc-macro"]
 
 extern crate proc_macro;

src/test/ui-fulldeps/lifetimes.rs

@@ -10,7 +10,7 @@
 
 // aux-build:lifetimes.rs
 
-#![feature(use_extern_macros, proc_macro_non_items)]
+#![feature(proc_macro_non_items)]
 
 extern crate lifetimes;
 

src/test/ui-fulldeps/proc-macro/auxiliary/generate-mod.rs

@@ -11,7 +11,6 @@
 // run-pass
 // no-prefer-dynamic
 
-#![feature(proc_macro)]
 #![crate_type = "proc-macro"]
 
 extern crate proc_macro;

src/test/ui-fulldeps/proc-macro/generate-mod.rs

@@ -12,7 +12,7 @@
 
 // aux-build:generate-mod.rs
 
-#![feature(use_extern_macros, proc_macro_gen, proc_macro_path_invoc)]
+#![feature(proc_macro_gen, proc_macro_path_invoc)]
 
 extern crate generate_mod;
 

src/test/ui-fulldeps/proc-macro/invalid-attributes.rs

@@ -11,7 +11,6 @@
 // no-prefer-dynamic
 
 #![crate_type = "proc-macro"]
-#![feature(proc_macro)]
 
 extern crate proc_macro;
 

src/test/ui-fulldeps/proc-macro/invalid-attributes.stderr

@@ -1,35 +1,35 @@
 error: `#[proc_macro]` attribute does not take any arguments
-  --> $DIR/invalid-attributes.rs:20:1
+  --> $DIR/invalid-attributes.rs:19:1
    |
 LL | #[proc_macro = "test"] //~ ERROR: does not take any arguments
    | ^^^^^^^^^^^^^^^^^^^^^^
 
 error: `#[proc_macro]` attribute does not take any arguments
-  --> $DIR/invalid-attributes.rs:23:1
+  --> $DIR/invalid-attributes.rs:22:1
    |
 LL | #[proc_macro()] //~ ERROR: does not take any arguments
    | ^^^^^^^^^^^^^^^
 
 error: `#[proc_macro]` attribute does not take any arguments
-  --> $DIR/invalid-attributes.rs:26:1
+  --> $DIR/invalid-attributes.rs:25:1
    |
 LL | #[proc_macro(x)] //~ ERROR: does not take any arguments
    | ^^^^^^^^^^^^^^^^
 
 error: `#[proc_macro_attribute]` attribute does not take any arguments
-  --> $DIR/invalid-attributes.rs:29:1
+  --> $DIR/invalid-attributes.rs:28:1
    |
 LL | #[proc_macro_attribute = "test"] //~ ERROR: does not take any arguments
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `#[proc_macro_attribute]` attribute does not take any arguments
-  --> $DIR/invalid-attributes.rs:32:1
+  --> $DIR/invalid-attributes.rs:31:1
    |
 LL | #[proc_macro_attribute()] //~ ERROR: does not take any arguments
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: `#[proc_macro_attribute]` attribute does not take any arguments
-  --> $DIR/invalid-attributes.rs:35:1
+  --> $DIR/invalid-attributes.rs:34:1
    |
 LL | #[proc_macro_attribute(x)] //~ ERROR: does not take any arguments
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^

src/test/ui-fulldeps/proc-macro/macro-namespace-reserved.rs

@@ -10,7 +10,7 @@
 
 // no-prefer-dynamic
 
-#![feature(proc_macro, decl_macro)]
+#![feature(decl_macro)]
 #![crate_type = "proc-macro"]
 
 extern crate proc_macro;

src/test/ui-fulldeps/proc-macro/non-root.rs

@@ -10,7 +10,6 @@
 
 // no-prefer-dynamic
 
-#![feature(proc_macro)]
 #![crate_type = "proc-macro"]
 
 extern crate proc_macro;

src/test/ui-fulldeps/proc-macro/non-root.stderr

@@ -1,5 +1,5 @@
 error: functions tagged with `#[proc_macro]` must currently reside in the root of the crate
-  --> $DIR/non-root.rs:21:5
+  --> $DIR/non-root.rs:20:5
    |
 LL |     pub fn foo(arg: TokenStream) -> TokenStream { arg }
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

src/test/ui-fulldeps/proc-macro/three-equals.rs

@@ -11,7 +11,7 @@
 // aux-build:three-equals.rs
 // ignore-stage1
 
-#![feature(use_extern_macros, proc_macro_non_items)]
+#![feature(proc_macro_non_items)]
 
 extern crate three_equals;
 

src/test/ui-fulldeps/resolve-error.rs

@@ -13,7 +13,7 @@
 // aux-build:attr_proc_macro.rs
 // aux-build:bang_proc_macro.rs
 
-#![feature(use_extern_macros)]
+#![feature(custom_attribute)]
 
 #[macro_use]
 extern crate derive_foo;
@@ -37,12 +37,10 @@ macro_rules! attr_proc_mac {
 //~^ ERROR cannot find
 struct Foo;
 
-#[attr_proc_macra]
-//~^ ERROR cannot find
+#[attr_proc_macra] // OK, interpreted as a custom attribute
 struct Bar;
 
-#[FooWithLongNan]
-//~^ ERROR cannot find
+#[FooWithLongNan]  // OK, interpreted as a custom attribute
 struct Asdf;
 
 #[derive(Dlone)]

src/test/ui-fulldeps/resolve-error.stderr

@@ -4,59 +4,47 @@ error: cannot find derive macro `FooWithLongNan` in this scope
 LL | #[derive(FooWithLongNan)]
    |          ^^^^^^^^^^^^^^ help: try: `FooWithLongName`
 
-error: cannot find attribute macro `attr_proc_macra` in this scope
-  --> $DIR/resolve-error.rs:40:3
-   |
-LL | #[attr_proc_macra]
-   |   ^^^^^^^^^^^^^^^ help: try: `attr_proc_macro`
-
-error: cannot find attribute macro `FooWithLongNan` in this scope
-  --> $DIR/resolve-error.rs:44:3
-   |
-LL | #[FooWithLongNan]
-   |   ^^^^^^^^^^^^^^
-
 error: cannot find derive macro `Dlone` in this scope
-  --> $DIR/resolve-error.rs:48:10
+  --> $DIR/resolve-error.rs:46:10
    |
 LL | #[derive(Dlone)]
    |          ^^^^^ help: try: `Clone`
 
 error: cannot find derive macro `Dlona` in this scope
-  --> $DIR/resolve-error.rs:52:10
+  --> $DIR/resolve-error.rs:50:10
    |
 LL | #[derive(Dlona)]
    |          ^^^^^ help: try: `Clona`
 
 error: cannot find derive macro `attr_proc_macra` in this scope
-  --> $DIR/resolve-error.rs:56:10
+  --> $DIR/resolve-error.rs:54:10
    |
 LL | #[derive(attr_proc_macra)]
    |          ^^^^^^^^^^^^^^^
 
 error: cannot find macro `FooWithLongNama!` in this scope
-  --> $DIR/resolve-error.rs:61:5
+  --> $DIR/resolve-error.rs:59:5
    |
 LL |     FooWithLongNama!();
    |     ^^^^^^^^^^^^^^^ help: you could try the macro: `FooWithLongNam`
 
 error: cannot find macro `attr_proc_macra!` in this scope
-  --> $DIR/resolve-error.rs:64:5
+  --> $DIR/resolve-error.rs:62:5
    |
 LL |     attr_proc_macra!();
    |     ^^^^^^^^^^^^^^^ help: you could try the macro: `attr_proc_mac`
 
 error: cannot find macro `Dlona!` in this scope
-  --> $DIR/resolve-error.rs:67:5
+  --> $DIR/resolve-error.rs:65:5
    |
 LL |     Dlona!();
    |     ^^^^^
 
 error: cannot find macro `bang_proc_macrp!` in this scope
-  --> $DIR/resolve-error.rs:70:5
+  --> $DIR/resolve-error.rs:68:5
    |
 LL |     bang_proc_macrp!();
    |     ^^^^^^^^^^^^^^^ help: you could try the macro: `bang_proc_macro`
 
-error: aborting due to 10 previous errors
+error: aborting due to 8 previous errors
 

src/test/ui/custom-attribute-multisegment.rs

@@ -1,4 +1,4 @@
-// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -8,18 +8,11 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// aux-build:attr_proc_macro.rs
-// ignore-tidy-linelength
+// Unresolved multi-segment attributes are not treated as custom.
 
-#![feature(use_extern_macros, custom_attribute)]
-//~^ ERROR Cannot use `#![feature(use_extern_macros)]` and `#![feature(custom_attribute)] at the same time
+#![feature(custom_attribute, proc_macro_path_invoc)]
 
-extern crate attr_proc_macro;
-use attr_proc_macro::attr_proc_macro;
+mod existent {}
 
-#[attr_proc_macro]
-fn foo() {}
-
-fn main() {
-    foo();
-}
+#[existent::nonexistent] //~ ERROR failed to resolve. Could not find `nonexistent` in `existent`
+fn main() {}

src/test/ui/custom-attribute-multisegment.stderr

@@ -0,0 +1,9 @@
+error[E0433]: failed to resolve. Could not find `nonexistent` in `existent`
+  --> $DIR/custom-attribute-multisegment.rs:17:13
+   |
+LL | #[existent::nonexistent] //~ ERROR failed to resolve. Could not find `nonexistent` in `existent`
+   |             ^^^^^^^^^^^ Could not find `nonexistent` in `existent`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0433`.

src/test/ui/feature-gate-macros_in_extern.rs

@@ -27,9 +27,9 @@ macro_rules! emits_nothing(
 #[link(name = "rust_test_helpers", kind = "static")]
 extern {
     returns_isize!(rust_get_test_int);
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental.
+    //~^ ERROR macro invocations in `extern {}` blocks are experimental
     takes_u32_returns_u32!(rust_dbg_extern_identity_u32);
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental.
+    //~^ ERROR macro invocations in `extern {}` blocks are experimental
     emits_nothing!();
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental.
+    //~^ ERROR macro invocations in `extern {}` blocks are experimental
 }

src/test/ui/feature-gate-macros_in_extern.stderr

@@ -1,4 +1,4 @@
-error[E0658]: macro and proc-macro invocations in `extern {}` blocks are experimental. (see issue #49476)
+error[E0658]: macro invocations in `extern {}` blocks are experimental (see issue #49476)
   --> $DIR/feature-gate-macros_in_extern.rs:29:5
    |
 LL |     returns_isize!(rust_get_test_int);
@@ -6,7 +6,7 @@ LL |     returns_isize!(rust_get_test_int);
    |
    = help: add #![feature(macros_in_extern)] to the crate attributes to enable
 
-error[E0658]: macro and proc-macro invocations in `extern {}` blocks are experimental. (see issue #49476)
+error[E0658]: macro invocations in `extern {}` blocks are experimental (see issue #49476)
   --> $DIR/feature-gate-macros_in_extern.rs:31:5
    |
 LL |     takes_u32_returns_u32!(rust_dbg_extern_identity_u32);
@@ -14,7 +14,7 @@ LL |     takes_u32_returns_u32!(rust_dbg_extern_identity_u32);
    |
    = help: add #![feature(macros_in_extern)] to the crate attributes to enable
 
-error[E0658]: macro and proc-macro invocations in `extern {}` blocks are experimental. (see issue #49476)
+error[E0658]: macro invocations in `extern {}` blocks are experimental (see issue #49476)
   --> $DIR/feature-gate-macros_in_extern.rs:33:5
    |
 LL |     emits_nothing!();

src/test/ui/imports/macros.rs

@@ -10,7 +10,7 @@
 
 // aux-build:two_macros.rs
 
-#![feature(item_like_imports, use_extern_macros)]
+#![feature(use_extern_macros)]
 
 extern crate two_macros; // two identity macros `m` and `n`
 

src/test/ui/issue-11692-2.rs

@@ -10,5 +10,5 @@
 
 fn main() {
     concat!(test!());
-    //~^ ERROR expected a macro, found non-macro attribute
+    //~^ ERROR expected a macro, found built-in attribute
 }

src/test/ui/issue-11692-2.stderr

@@ -1,4 +1,4 @@
-error: expected a macro, found non-macro attribute
+error: expected a macro, found built-in attribute
   --> $DIR/issue-11692-2.rs:12:13
    |
 LL |     concat!(test!());

src/test/ui/macro-path-prelude-fail-3.rs

@@ -10,9 +10,9 @@
 
 #![feature(use_extern_macros)]
 
-#[derive(inline)] //~ ERROR expected a macro, found non-macro attribute
+#[derive(inline)] //~ ERROR expected a macro, found built-in attribute
 struct S;
 
 fn main() {
-    inline!(); //~ ERROR expected a macro, found non-macro attribute
+    inline!(); //~ ERROR expected a macro, found built-in attribute
 }

src/test/ui/macro-path-prelude-fail-3.stderr

@@ -1,13 +1,13 @@
-error: expected a macro, found non-macro attribute
+error: expected a macro, found built-in attribute
   --> $DIR/macro-path-prelude-fail-3.rs:13:10
    |
-LL | #[derive(inline)] //~ ERROR expected a macro, found non-macro attribute
+LL | #[derive(inline)] //~ ERROR expected a macro, found built-in attribute
    |          ^^^^^^
 
-error: expected a macro, found non-macro attribute
+error: expected a macro, found built-in attribute
   --> $DIR/macro-path-prelude-fail-3.rs:17:5
    |
-LL |     inline!(); //~ ERROR expected a macro, found non-macro attribute
+LL |     inline!(); //~ ERROR expected a macro, found built-in attribute
    |     ^^^^^^
 
 error: aborting due to 2 previous errors

src/test/ui/tool-attributes-disabled-2.rs

@@ -11,9 +11,5 @@
 // If macro modularization (`use_extern_macros`) is not enabled,
 // then tool attributes are treated as custom attributes.
 
-// compile-pass
-
-#![feature(custom_attribute)]
-
-#[rustfmt::bar]
+#[rustfmt::bar] //~ ERROR attribute `rustfmt::bar` is currently unknown to the compiler
 fn main() {}

src/test/ui/tool-attributes-disabled-2.stderr

@@ -0,0 +1,11 @@
+error[E0658]: The attribute `rustfmt::bar` is currently unknown to the compiler and may have meaning added to it in the future (see issue #29642)
+  --> $DIR/tool-attributes-disabled-2.rs:14:1
+   |
+LL | #[rustfmt::bar] //~ ERROR attribute `rustfmt::bar` is currently unknown to the compiler
+   | ^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(custom_attribute)] to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/tool-attributes-misplaced-1.rs

@@ -8,15 +8,15 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(tool_attributes)]
+#![feature(tool_attributes, custom_attribute)]
 
 type A = rustfmt; //~ ERROR expected type, found tool module `rustfmt`
-type B = rustfmt::skip; //~ ERROR expected type, found non-macro attribute `rustfmt::skip`
+type B = rustfmt::skip; //~ ERROR expected type, found tool attribute `rustfmt::skip`
 
 #[derive(rustfmt)] //~ ERROR cannot find derive macro `rustfmt` in this scope
 struct S;
 
-#[rustfmt] //~ ERROR cannot find attribute macro `rustfmt` in this scope
+#[rustfmt] // OK, interpreted as a custom attribute
 fn check() {}
 
 #[rustfmt::skip] // OK
@@ -24,5 +24,5 @@ fn main() {
     rustfmt; //~ ERROR expected value, found tool module `rustfmt`
     rustfmt!(); //~ ERROR cannot find macro `rustfmt!` in this scope
 
-    rustfmt::skip; //~ ERROR expected value, found non-macro attribute `rustfmt::skip`
+    rustfmt::skip; //~ ERROR expected value, found tool attribute `rustfmt::skip`
 }

src/test/ui/tool-attributes-misplaced-1.stderr

@@ -4,12 +4,6 @@ error: cannot find derive macro `rustfmt` in this scope
 LL | #[derive(rustfmt)] //~ ERROR cannot find derive macro `rustfmt` in this scope
    |          ^^^^^^^
 
-error: cannot find attribute macro `rustfmt` in this scope
-  --> $DIR/tool-attributes-misplaced-1.rs:19:3
-   |
-LL | #[rustfmt] //~ ERROR cannot find attribute macro `rustfmt` in this scope
-   |   ^^^^^^^
-
 error: cannot find macro `rustfmt!` in this scope
   --> $DIR/tool-attributes-misplaced-1.rs:25:5
    |
@@ -22,10 +16,10 @@ error[E0573]: expected type, found tool module `rustfmt`
 LL | type A = rustfmt; //~ ERROR expected type, found tool module `rustfmt`
    |          ^^^^^^^ not a type
 
-error[E0573]: expected type, found non-macro attribute `rustfmt::skip`
+error[E0573]: expected type, found tool attribute `rustfmt::skip`
   --> $DIR/tool-attributes-misplaced-1.rs:14:10
    |
-LL | type B = rustfmt::skip; //~ ERROR expected type, found non-macro attribute `rustfmt::skip`
+LL | type B = rustfmt::skip; //~ ERROR expected type, found tool attribute `rustfmt::skip`
    |          ^^^^^^^^^^^^^ not a type
 
 error[E0423]: expected value, found tool module `rustfmt`
@@ -34,13 +28,13 @@ error[E0423]: expected value, found tool module `rustfmt`
 LL |     rustfmt; //~ ERROR expected value, found tool module `rustfmt`
    |     ^^^^^^^ not a value
 
-error[E0423]: expected value, found non-macro attribute `rustfmt::skip`
+error[E0423]: expected value, found tool attribute `rustfmt::skip`
   --> $DIR/tool-attributes-misplaced-1.rs:27:5
    |
-LL |     rustfmt::skip; //~ ERROR expected value, found non-macro attribute `rustfmt::skip`
+LL |     rustfmt::skip; //~ ERROR expected value, found tool attribute `rustfmt::skip`
    |     ^^^^^^^^^^^^^ not a value
 
-error: aborting due to 7 previous errors
+error: aborting due to 6 previous errors
 
 Some errors occurred: E0423, E0573.
 For more information about an error, try `rustc --explain E0423`.

src/test/ui/tool-attributes-misplaced-2.rs

@@ -10,9 +10,9 @@
 
 #![feature(tool_attributes)]
 
-#[derive(rustfmt::skip)] //~ ERROR expected a macro, found non-macro attribute
+#[derive(rustfmt::skip)] //~ ERROR expected a macro, found tool attribute
 struct S;
 
 fn main() {
-    rustfmt::skip!(); //~ ERROR expected a macro, found non-macro attribute
+    rustfmt::skip!(); //~ ERROR expected a macro, found tool attribute
 }

src/test/ui/tool-attributes-misplaced-2.stderr

@@ -1,13 +1,13 @@
-error: expected a macro, found non-macro attribute
+error: expected a macro, found tool attribute
   --> $DIR/tool-attributes-misplaced-2.rs:13:10
    |
-LL | #[derive(rustfmt::skip)] //~ ERROR expected a macro, found non-macro attribute
+LL | #[derive(rustfmt::skip)] //~ ERROR expected a macro, found tool attribute
    |          ^^^^^^^^^^^^^
 
-error: expected a macro, found non-macro attribute
+error: expected a macro, found tool attribute
   --> $DIR/tool-attributes-misplaced-2.rs:17:5
    |
-LL |     rustfmt::skip!(); //~ ERROR expected a macro, found non-macro attribute
+LL |     rustfmt::skip!(); //~ ERROR expected a macro, found tool attribute
    |     ^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors