Clean up lang_items::extract

Noted in rust-lang#87739 (review),
lang_items::extract no longer needs to take a closure.

Author: ehuss

compiler/rustc_hir/src/lang_items.rs

@@ -151,20 +151,12 @@ impl<CTX> HashStable<CTX> for LangItem {
 /// Extracts the first `lang = "$name"` out of a list of attributes.
 /// The attributes `#[panic_handler]` and `#[alloc_error_handler]`
 /// are also extracted out when found.
-///
-/// About the `check_name` argument: passing in a `Session` would be simpler,
-/// because then we could call `Session::check_name` directly. But we want to
-/// avoid the need for `rustc_hir` to depend on `rustc_session`, so we
-/// use a closure instead.
-pub fn extract<'a, F>(check_name: F, attrs: &'a [ast::Attribute]) -> Option<(Symbol, Span)>
-where
-    F: Fn(&'a ast::Attribute, Symbol) -> bool,
-{
+pub fn extract(attrs: &[ast::Attribute]) -> Option<(Symbol, Span)> {
     attrs.iter().find_map(|attr| {
         Some(match attr {
-            _ if check_name(attr, sym::lang) => (attr.value_str()?, attr.span),
-            _ if check_name(attr, sym::panic_handler) => (sym::panic_impl, attr.span),
-            _ if check_name(attr, sym::alloc_error_handler) => (sym::oom, attr.span),
+            _ if attr.has_name(sym::lang) => (attr.value_str()?, attr.span),
+            _ if attr.has_name(sym::panic_handler) => (sym::panic_impl, attr.span),
+            _ if attr.has_name(sym::alloc_error_handler) => (sym::oom, attr.span),
             _ => return None,
         })
     })

compiler/rustc_hir/src/weak_lang_items.rs

@@ -18,13 +18,9 @@ pub static WEAK_ITEMS_REFS: SyncLazy<StableMap<Symbol, LangItem>> = SyncLazy::ne
     map
 });
 
-/// The `check_name` argument avoids the need for `rustc_hir` to depend on
-/// `rustc_session`.
-pub fn link_name<'a, F>(check_name: F, attrs: &'a [ast::Attribute]) -> Option<Symbol>
-where
-    F: Fn(&'a ast::Attribute, Symbol) -> bool
+pub fn link_name(attrs: &[ast::Attribute]) -> Option<Symbol>
 {
-    lang_items::extract(check_name, attrs).and_then(|(name, _)| {
+    lang_items::extract(attrs).and_then(|(name, _)| {
         $(if name == sym::$name {
             Some(sym::$sym)
         } else)* {

compiler/rustc_passes/src/lang_items.rs

@@ -10,7 +10,6 @@
 use crate::check_attr::target_from_impl_item;
 use crate::weak_lang_items;
 
-use rustc_ast::Attribute;
 use rustc_errors::{pluralize, struct_span_err};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
@@ -57,8 +56,7 @@ impl<'tcx> LanguageItemCollector<'tcx> {
 
     fn check_for_lang(&mut self, actual_target: Target, hir_id: HirId) {
         let attrs = self.tcx.hir().attrs(hir_id);
-        let check_name = |attr: &Attribute, sym| attr.has_name(sym);
-        if let Some((value, span)) = extract(check_name, &attrs) {
+        if let Some((value, span)) = extract(&attrs) {
             match ITEM_REFS.get(&value).cloned() {
                 // Known lang item with attribute on correct target.
                 Some((item_index, expected_target)) if actual_target == expected_target => {

compiler/rustc_passes/src/weak_lang_items.rs

@@ -1,6 +1,5 @@
 //! Validity checking for weak lang items
 
-use rustc_ast::Attribute;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
@@ -103,9 +102,8 @@ impl<'a, 'tcx, 'v> Visitor<'v> for Context<'a, 'tcx> {
     }
 
     fn visit_foreign_item(&mut self, i: &hir::ForeignItem<'_>) {
-        let check_name = |attr: &Attribute, sym| attr.has_name(sym);
         let attrs = self.tcx.hir().attrs(i.hir_id());
-        if let Some((lang_item, _)) = lang_items::extract(check_name, attrs) {
+        if let Some((lang_item, _)) = lang_items::extract(attrs) {
             self.register(lang_item, i.span);
         }
         intravisit::walk_foreign_item(self, i)

compiler/rustc_typeck/src/collect.rs

@@ -21,7 +21,6 @@ use crate::constrained_generic_params as cgp;
 use crate::errors;
 use crate::middle::resolve_lifetime as rl;
 use rustc_ast as ast;
-use rustc_ast::Attribute;
 use rustc_ast::{MetaItemKind, NestedMetaItem};
 use rustc_attr::{list_contains_name, InlineAttr, InstructionSetAttr, OptimizeAttr};
 use rustc_data_structures::captures::Captures;
@@ -3120,8 +3119,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs {
     if tcx.is_weak_lang_item(id) {
         codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
     }
-    let check_name = |attr: &Attribute, sym| attr.has_name(sym);
-    if let Some(name) = weak_lang_items::link_name(check_name, attrs) {
+    if let Some(name) = weak_lang_items::link_name(attrs) {
         codegen_fn_attrs.export_name = Some(name);
         codegen_fn_attrs.link_name = Some(name);
     }