Rollup merge of #132341 - compiler-errors:raw-lt-prefix-id, r=chenyukang

Reject raw lifetime followed by `'`, like regular lifetimes do

See comment. We want to reject cases like `'r#long'id`, which currently gets interpreted as a raw lifetime (`'r#long`) followed by a lifetime (`'id`). This could have alternative lexes, such as an overlong char literal (`'r#long'`) followed by an identifier (`id`). To avoid committing to this in any case, let's reject the whole thing.

`@mattheww,` is this what you were looking for in https://github.com/rust-lang/reference/pull/1603#issuecomment-2339237325? I'd say ignore the details about the specific error message (the fact that this gets reinterpreted as a char literal is 🤷), just that because this causes a lexer error we're effectively saving syntactical space like you wanted.

1 files changed, 11 insertions, 1 deletions

diff --git a/compiler/rustc_lexer/src/lib.rs b/compiler/rustc_lexer/src/lib.rs
index b0ab50dd773..f9f2a14dbd2 100644
--- a/compiler/rustc_lexer/src/lib.rs
+++ b/compiler/rustc_lexer/src/lib.rs
@@ -715,7 +715,17 @@ impl Cursor<'_> {
             self.bump();
             self.bump();
             self.eat_while(is_id_continue);
-            return RawLifetime;
+            match self.first() {
+                '\'' => {
+                    // Check if after skipping literal contents we've met a closing
+                    // single quote (which means that user attempted to create a
+                    // string with single quotes).
+                    self.bump();
+                    let kind = Char { terminated: true };
+                    return Literal { kind, suffix_start: self.pos_within_token() };
+                }
+                _ => return RawLifetime,
+            }
         }
 
         // Either a lifetime or a character literal with