Fix proc-macro attributes being shadowed by their functions in IDE layer

Author: Veykril

crates/hir/src/semantics.rs

@@ -329,6 +329,10 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.resolve_path(path)
     }
 
+    pub fn resolve_path_as_macro(&self, path: &ast::Path) -> Option<MacroDef> {
+        self.imp.resolve_path_as_macro(path)
+    }
+
     pub fn resolve_extern_crate(&self, extern_crate: &ast::ExternCrate) -> Option<Crate> {
         self.imp.resolve_extern_crate(extern_crate)
     }
@@ -845,6 +849,12 @@ impl<'db> SemanticsImpl<'db> {
         self.analyze(path.syntax()).resolve_path(self.db, path)
     }
 
+    // FIXME: This shouldn't exist, but is currently required to always resolve attribute paths in
+    // the IDE layer due to namespace collisions
+    fn resolve_path_as_macro(&self, path: &ast::Path) -> Option<MacroDef> {
+        self.analyze(path.syntax()).resolve_path_as_macro(self.db, path)
+    }
+
     fn resolve_extern_crate(&self, extern_crate: &ast::ExternCrate) -> Option<Crate> {
         let krate = self.scope(extern_crate.syntax()).krate()?;
         krate.dependencies(self.db).into_iter().find_map(|dep| {

crates/hir/src/source_analyzer.rs

@@ -246,6 +246,18 @@ impl SourceAnalyzer {
         }
     }
 
+    pub(crate) fn resolve_path_as_macro(
+        &self,
+        db: &dyn HirDatabase,
+        path: &ast::Path,
+    ) -> Option<MacroDef> {
+        // This must be a normal source file rather than macro file.
+        let hygiene = Hygiene::new(db.upcast(), self.file_id);
+        let ctx = body::LowerCtx::with_hygiene(db.upcast(), &hygiene);
+        let hir_path = Path::from_src(path.clone(), &ctx)?;
+        resolve_hir_path_as_macro(db, &self.resolver, &hir_path)
+    }
+
     pub(crate) fn resolve_path(
         &self,
         db: &dyn HirDatabase,

crates/ide/src/syntax_highlighting/test_data/highlighting.html

@@ -43,7 +43,7 @@
 <pre><code><span class="keyword">use</span> <span class="module">inner</span><span class="operator">::</span><span class="brace">{</span><span class="self_keyword">self</span> <span class="keyword">as</span> <span class="module declaration">inner_mod</span><span class="brace">}</span><span class="semicolon">;</span>
 <span class="keyword">mod</span> <span class="module declaration">inner</span> <span class="brace">{</span><span class="brace">}</span>
 
-<span class="attribute attribute">#</span><span class="attribute attribute">[</span><span class="module attribute">proc_macros</span><span class="operator attribute">::</span><span class="builtin_attr attribute">identity</span><span class="attribute attribute">]</span>
+<span class="attribute attribute">#</span><span class="attribute attribute">[</span><span class="module attribute">proc_macros</span><span class="operator attribute">::</span><span class="macro attribute">identity</span><span class="attribute attribute">]</span>
 <span class="keyword">pub</span> <span class="keyword">mod</span> <span class="module declaration public">ops</span> <span class="brace">{</span>
     <span class="attribute attribute">#</span><span class="attribute attribute">[</span><span class="builtin_attr attribute">lang</span> <span class="operator attribute">=</span> <span class="string_literal attribute">"fn_once"</span><span class="attribute attribute">]</span>
     <span class="keyword">pub</span> <span class="keyword">trait</span> <span class="trait declaration public">FnOnce</span><span class="angle">&lt;</span><span class="type_param declaration">Args</span><span class="angle">&gt;</span> <span class="brace">{</span><span class="brace">}</span>

crates/ide_db/src/defs.rs

@@ -433,20 +433,20 @@ impl NameRefClass {
                 .find_map(ast::Attr::cast)
                 .map(|attr| attr.path().as_ref() == Some(&top_path));
             return match is_attribute_path {
-                Some(true) => sema.resolve_path(&path).and_then(|resolved| {
-                    match resolved {
-                        // Don't wanna collide with builtin attributes here like `test` hence guard
-                        // so only resolve to modules that aren't the last segment
-                        PathResolution::Def(module @ ModuleDef::Module(_)) if path != top_path => {
-                            cov_mark::hit!(name_ref_classify_attr_path_qualifier);
-                            Some(NameRefClass::Definition(Definition::ModuleDef(module)))
-                        }
-                        PathResolution::Macro(mac) if mac.kind() == hir::MacroKind::Attr => {
-                            Some(NameRefClass::Definition(Definition::Macro(mac)))
-                        }
-                        _ => None,
+                Some(true) if path == top_path => sema
+                    .resolve_path_as_macro(&path)
+                    .filter(|mac| mac.kind() == hir::MacroKind::Attr)
+                    .map(Definition::Macro)
+                    .map(NameRefClass::Definition),
+                // in case of the path being a qualifier, don't resolve to anything but a module
+                Some(true) => match sema.resolve_path(&path)? {
+                    PathResolution::Def(module @ ModuleDef::Module(_)) => {
+                        cov_mark::hit!(name_ref_classify_attr_path_qualifier);
+                        Some(NameRefClass::Definition(Definition::ModuleDef(module)))
                     }
-                }),
+                    _ => None,
+                },
+                // inside attribute, but our path isn't part of the attribute's path(might be in its expression only)
                 Some(false) => None,
                 None => sema.resolve_path(&path).map(Into::into).map(NameRefClass::Definition),
             };