Lint against keyword lifetimes in keyword_idents

compiler/rustc_lint/src/builtin.rs

@@ -1851,9 +1851,16 @@ impl KeywordIdents {
                 TokenTree::Token(token, _) => {
                     if let Some((ident, token::IdentIsRaw::No)) = token.ident() {
                         if !prev_dollar {
-                            self.check_ident_token(cx, UnderMacro(true), ident);
+                            self.check_ident_token(cx, UnderMacro(true), ident, "");
                         }
-                    } else if *token == TokenKind::Dollar {
+                    } else if let Some((ident, token::IdentIsRaw::No)) = token.lifetime() {
+                        self.check_ident_token(
+                            cx,
+                            UnderMacro(true),
+                            ident.without_first_quote(),
+                            "'",
+                        );
+                    } else if token.kind == TokenKind::Dollar {
                         prev_dollar = true;
                         continue;
                     }
@@ -1869,6 +1876,7 @@ impl KeywordIdents {
         cx: &EarlyContext<'_>,
         UnderMacro(under_macro): UnderMacro,
         ident: Ident,
+        prefix: &'static str,
     ) {
         let (lint, edition) = match ident.name {
             kw::Async | kw::Await | kw::Try => (KEYWORD_IDENTS_2018, Edition::Edition2018),
@@ -1902,7 +1910,7 @@ impl KeywordIdents {
         cx.emit_span_lint(
             lint,
             ident.span,
-            BuiltinKeywordIdents { kw: ident, next: edition, suggestion: ident.span },
+            BuiltinKeywordIdents { kw: ident, next: edition, suggestion: ident.span, prefix },
         );
     }
 }
@@ -1915,7 +1923,11 @@ impl EarlyLintPass for KeywordIdents {
         self.check_tokens(cx, &mac.args.tokens);
     }
     fn check_ident(&mut self, cx: &EarlyContext<'_>, ident: Ident) {
-        self.check_ident_token(cx, UnderMacro(false), ident);
+        if ident.name.as_str().starts_with('\'') {
+            self.check_ident_token(cx, UnderMacro(false), ident.without_first_quote(), "'");
+        } else {
+            self.check_ident_token(cx, UnderMacro(false), ident, "");
+        }
     }
 }
 

compiler/rustc_lint/src/lints.rs

@@ -363,8 +363,9 @@ pub(crate) enum BuiltinEllipsisInclusiveRangePatternsLint {
 pub(crate) struct BuiltinKeywordIdents {
     pub kw: Ident,
     pub next: Edition,
-    #[suggestion(code = "r#{kw}", applicability = "machine-applicable")]
+    #[suggestion(code = "{prefix}r#{kw}", applicability = "machine-applicable")]
     pub suggestion: Span,
+    pub prefix: &'static str,
 }
 
 #[derive(LintDiagnostic)]

tests/ui/rust-2024/gen-kw.e2015.stderr

@@ -31,5 +31,14 @@ LL |     () => { mod test { fn gen() {} } }
    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2024!
    = note: for more information, see issue #49716 <https://github.com/rust-lang/rust/issues/49716>
 
-error: aborting due to 3 previous errors
+error: `gen` is a keyword in the 2024 edition
+  --> $DIR/gen-kw.rs:25:9
+   |
+LL | fn test<'gen>() {}
+   |         ^^^^ help: you can use a raw identifier to stay compatible: `'r#gen`
+   |
+   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2024!
+   = note: for more information, see issue #49716 <https://github.com/rust-lang/rust/issues/49716>
+
+error: aborting due to 4 previous errors
 

tests/ui/rust-2024/gen-kw.e2018.stderr

@@ -31,5 +31,14 @@ LL |     () => { mod test { fn gen() {} } }
    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2024!
    = note: for more information, see issue #49716 <https://github.com/rust-lang/rust/issues/49716>
 
-error: aborting due to 3 previous errors
+error: `gen` is a keyword in the 2024 edition
+  --> $DIR/gen-kw.rs:25:9
+   |
+LL | fn test<'gen>() {}
+   |         ^^^^ help: you can use a raw identifier to stay compatible: `'r#gen`
+   |
+   = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2024!
+   = note: for more information, see issue #49716 <https://github.com/rust-lang/rust/issues/49716>
+
+error: aborting due to 4 previous errors
 

tests/ui/rust-2024/gen-kw.rs

@@ -22,4 +22,9 @@ macro_rules! t {
     //[e2018]~| WARNING this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2024!
 }
 
+fn test<'gen>() {}
+//~^ ERROR `gen` is a keyword in the 2024 edition
+//[e2015]~| WARNING this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2024!
+//[e2018]~| WARNING this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2024!
+
 t!();