fix: escape keywords used as names in earlier editions

Author: lowr

crates/hir-expand/src/name.rs

@@ -90,10 +90,16 @@ impl Name {
 
     /// Resolve a name from the text of token.
     fn resolve(raw_text: &str) -> Name {
-        // When `raw_text` starts with "r#" but the name does not coincide with any
-        // keyword, we never need the prefix so we strip it.
         match raw_text.strip_prefix("r#") {
+            // When `raw_text` starts with "r#" but the name does not coincide with any
+            // keyword, we never need the prefix so we strip it.
             Some(text) if !is_raw_identifier(text) => Name::new_text(SmolStr::new(text)),
+            // Keywords (in the current edition) *can* be used as a name in earlier editions of
+            // Rust, e.g. "try" in Rust 2015. Even in such cases, we keep track of them in their
+            // escaped form.
+            None if is_raw_identifier(raw_text) => {
+                Name::new_text(SmolStr::from_iter(["r#", raw_text]))
+            }
             _ => Name::new_text(raw_text.into()),
         }
     }

crates/ide-db/src/search.rs

@@ -402,7 +402,9 @@ impl<'a> FindUsages<'a> {
                             .or_else(|| ty.as_builtin().map(|builtin| builtin.name()))
                     })
                 };
-                self.def.name(sema.db).or_else(self_kw_refs).map(|it| it.to_smol_str())
+                // We need to unescape the name in case it is written without "r#" in earlier
+                // editions of Rust where it isn't a keyword.
+                self.def.name(sema.db).or_else(self_kw_refs).map(|it| it.unescaped().to_smol_str())
             }
         };
         let name = match &name {