Auto merge of #149790 - JonathanBrouwer:attr-path-perf, r=<try>

[PERF] How much does lowering the spans in `AttrPath` matter?

Author: rust-bors[bot]

compiler/rustc_attr_parsing/src/attributes/cfg.rs

@@ -355,7 +355,7 @@ pub fn parse_cfg_attr(
                 span,
                 attr_span: cfg_attr.span,
                 template: CFG_ATTR_TEMPLATE,
-                path: AttrPath::from_ast(&cfg_attr.get_normal_item().path, identity),
+                path: AttrPath::from_ast(&cfg_attr.get_normal_item().path),
                 description: ParsedDescription::Attribute,
                 reason,
                 suggestions: CFG_ATTR_TEMPLATE

compiler/rustc_attr_parsing/src/interface.rs

@@ -311,7 +311,7 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
                 // }
                 ast::AttrKind::Normal(n) => {
                     attr_paths.push(PathParser(Cow::Borrowed(&n.item.path)));
-                    let attr_path = AttrPath::from_ast(&n.item.path, lower_span);
+                    let attr_path = AttrPath::from_ast(&n.item.path);
 
                     self.check_attribute_safety(
                         &attr_path,

compiler/rustc_attr_parsing/src/validate_attr.rs

@@ -165,7 +165,7 @@ pub fn check_builtin_meta_item(
     if deny_unsafety && let Safety::Unsafe(unsafe_span) = meta.unsafety {
         psess.dcx().emit_err(errors::InvalidAttrUnsafe {
             span: unsafe_span,
-            name: AttrPath::from_ast(&meta.path, identity),
+            name: AttrPath::from_ast(&meta.path),
         });
     }
 }

compiler/rustc_hir/src/hir.rs

@@ -1193,15 +1193,10 @@ impl IntoDiagArg for AttrPath {
 }
 
 impl AttrPath {
-    pub fn from_ast(path: &ast::Path, lower_span: impl Copy + Fn(Span) -> Span) -> Self {
+    pub fn from_ast(path: &ast::Path) -> Self {
         AttrPath {
-            segments: path
-                .segments
-                .iter()
-                .map(|i| Ident { name: i.ident.name, span: lower_span(i.ident.span) })
-                .collect::<Vec<_>>()
-                .into_boxed_slice(),
-            span: lower_span(path.span),
+            segments: path.segments.iter().map(|i| i.ident).collect::<Vec<_>>().into_boxed_slice(),
+            span: path.span,
         }
     }
 }