Avoid re-interning in `LateContext::get_def_path`

The def path printer in `get_def_path` essentially calls
`Symbol::intern(&symbol.to_string())` for simple symbols in a path.
This accounts for ~30% of the runtime of get_def_path.

We can avoid this by simply appending the symbol directly when available.

1 files changed, 4 insertions, 1 deletions

diff --git a/compiler/rustc_lint/src/context.rs b/compiler/rustc_lint/src/context.rs
index 3660bb3f780..5679d4566dc 100644
--- a/compiler/rustc_lint/src/context.rs
+++ b/compiler/rustc_lint/src/context.rs
@@ -812,7 +812,10 @@ impl<'tcx> LateContext<'tcx> {
                     return Ok(());
                 }
 
-                self.path.push(Symbol::intern(&disambiguated_data.data.to_string()));
+                self.path.push(match disambiguated_data.data.get_opt_name() {
+                    Some(sym) => sym,
+                    None => Symbol::intern(&disambiguated_data.data.to_string()),
+                });
                 Ok(())
             }