internal: Record unresolved derive invocations in hir

Author: Veykril

crates/hir/src/semantics.rs

@@ -18,13 +18,14 @@ use smallvec::{smallvec, SmallVec};
 use syntax::{
     algo::skip_trivia_token,
     ast::{self, HasAttrs, HasGenericParams, HasLoopBody},
-    match_ast, AstNode, Direction, SyntaxNode, SyntaxNodePtr, SyntaxToken, TextSize,
+    match_ast, AstNode, AstToken, Direction, SyntaxElement, SyntaxNode, SyntaxNodePtr, SyntaxToken,
+    TextSize, T,
 };
 
 use crate::{
     db::HirDatabase,
     semantics::source_to_def::{ChildContainer, SourceToDefCache, SourceToDefCtx},
-    source_analyzer::{resolve_hir_path, resolve_hir_path_as_macro, SourceAnalyzer},
+    source_analyzer::{resolve_hir_path, SourceAnalyzer},
     Access, AssocItem, BuiltinAttr, Callable, ConstParam, Crate, Field, Function, HasSource,
     HirFileId, Impl, InFile, Label, LifetimeParam, Local, MacroDef, Module, ModuleDef, Name, Path,
     ScopeDef, ToolModule, Trait, Type, TypeAlias, TypeParam, VariantDef,
@@ -354,6 +355,10 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.resolve_bind_pat_to_const(pat)
     }
 
+    pub fn resolve_derive_ident(&self, ident: &ast::Ident) -> Option<PathResolution> {
+        self.imp.resolve_derive_ident(ident)
+    }
+
     // FIXME: use this instead?
     // pub fn resolve_name_ref(&self, name_ref: &ast::NameRef) -> Option<???>;
 
@@ -894,6 +899,64 @@ impl<'db> SemanticsImpl<'db> {
         self.analyze(pat.syntax()).resolve_bind_pat_to_const(self.db, pat)
     }
 
+    fn resolve_derive_ident(&self, ident: &ast::Ident) -> Option<PathResolution> {
+        // derive macros are always at depth 2, tokentree -> meta -> attribute
+        let syntax = ident.syntax();
+        let attr = syntax.ancestors().nth(2).and_then(ast::Attr::cast)?;
+
+        let tt = attr.token_tree()?;
+        if !tt.syntax().text_range().contains_range(ident.syntax().text_range()) {
+            return None;
+        }
+
+        // Fetch hir::Attr definition
+        // FIXME: Move this to ToDef impl?
+        let adt = attr.syntax().parent().and_then(ast::Adt::cast)?;
+        let attr_pos = adt.attrs().position(|it| it == attr)?;
+        let attrs = {
+            let file_id = self.find_file(adt.syntax()).file_id;
+            let adt = InFile::new(file_id, adt);
+            let def = self.with_ctx(|ctx| ctx.adt_to_def(adt))?;
+            self.db.attrs(def.into())
+        };
+        let attr_def = attrs.get(attr_pos)?;
+
+        let mut derive_paths = attr_def.parse_path_comma_token_tree()?;
+        let derives = self.resolve_derive_macro(&attr)?;
+
+        let derive_idx = tt
+            .syntax()
+            .children_with_tokens()
+            .filter_map(SyntaxElement::into_token)
+            .take_while(|tok| tok != syntax)
+            .filter(|t| t.kind() == T![,])
+            .count();
+        let path_segment_idx = syntax
+            .siblings_with_tokens(Direction::Prev)
+            .filter_map(SyntaxElement::into_token)
+            .take_while(|tok| matches!(tok.kind(), T![:] | T![ident]))
+            .filter(|tok| tok.kind() == T![ident])
+            .count();
+
+        let mut mod_path = derive_paths.nth(derive_idx)?;
+
+        if path_segment_idx < mod_path.len() {
+            // the path for the given ident is a qualifier, resolve to module if possible
+            while path_segment_idx < mod_path.len() {
+                mod_path.pop_segment();
+            }
+            resolve_hir_path(
+                self.db,
+                &self.scope(attr.syntax()).resolver,
+                &Path::from_known_path(mod_path, []),
+            )
+            .filter(|res| matches!(res, PathResolution::Def(ModuleDef::Module(_))))
+        } else {
+            // otherwise fetch the derive
+            derives.get(derive_idx)?.map(PathResolution::Macro)
+        }
+    }
+
     fn record_literal_missing_fields(&self, literal: &ast::RecordExpr) -> Vec<(Field, Type)> {
         self.analyze(literal.syntax())
             .record_literal_missing_fields(self.db, literal)
@@ -1230,14 +1293,4 @@ impl<'a> SemanticsScope<'a> {
         let path = Path::from_src(path.clone(), &ctx)?;
         resolve_hir_path(self.db, &self.resolver, &path)
     }
-
-    /// Resolve a path as-if it was written at the given scope. This is
-    /// necessary a heuristic, as it doesn't take hygiene into account.
-    // FIXME: This special casing solely exists for attributes for now
-    // ideally we should have a path resolution infra that properly knows about overlapping namespaces
-    pub fn speculative_resolve_as_mac(&self, path: &ast::Path) -> Option<MacroDef> {
-        let ctx = body::LowerCtx::new(self.db.upcast(), self.file_id);
-        let path = Path::from_src(path.clone(), &ctx)?;
-        resolve_hir_path_as_macro(self.db, &self.resolver, &path)
-    }
 }

crates/hir_def/src/attr.rs

@@ -720,11 +720,8 @@ impl Attr {
         Self::from_src(db, ast, hygiene, id)
     }
 
-    /// Parses this attribute as a `#[derive]`, returns an iterator that yields all contained paths
-    /// to derive macros.
-    ///
-    /// Returns `None` when the attribute does not have a well-formed `#[derive]` attribute input.
-    pub(crate) fn parse_derive(&self) -> Option<impl Iterator<Item = ModPath> + '_> {
+    /// Parses this attribute as a token tree consisting of comma separated paths.
+    pub fn parse_path_comma_token_tree(&self) -> Option<impl Iterator<Item = ModPath> + '_> {
         let args = match self.input.as_deref() {
             Some(AttrInput::TokenTree(args, _)) => args,
             _ => return None,

crates/hir_def/src/nameres/collector.rs

@@ -1145,7 +1145,7 @@ impl DefCollector<'_> {
                             }
                         }
 
-                        match attr.parse_derive() {
+                        match attr.parse_path_comma_token_tree() {
                             Some(derive_macros) => {
                                 let mut len = 0;
                                 for (idx, path) in derive_macros.enumerate() {

crates/ide/src/goto_definition.rs

@@ -1381,6 +1381,18 @@ mod foo {
            // ^^^^
 }
 #[derive(foo::Copy$0)]
+struct Foo;
+            "#,
+        );
+        check(
+            r#"
+//- minicore:derive
+mod foo {
+ // ^^^
+    #[rustc_builtin_macro]
+    pub macro Copy {}
+}
+#[derive(foo$0::Copy)]
 struct Foo;
             "#,
         );

crates/ide/src/syntax_highlighting/highlight.rs

@@ -3,7 +3,7 @@
 use hir::{AsAssocItem, HasVisibility, Semantics};
 use ide_db::{
     defs::{Definition, NameClass, NameRefClass},
-    helpers::{try_resolve_derive_input, FamousDefs},
+    helpers::FamousDefs,
     RootDatabase, SymbolKind,
 };
 use rustc_hash::FxHashMap;
@@ -40,13 +40,8 @@ pub(super) fn token(
         BYTE => HlTag::ByteLiteral.into(),
         CHAR => HlTag::CharLiteral.into(),
         IDENT if parent_matches::<ast::TokenTree>(&token) => {
-            match token.ancestors().nth(2).and_then(ast::Attr::cast) {
-                Some(attr) => {
-                    match try_resolve_derive_input(sema, &attr, &ast::Ident::cast(token).unwrap()) {
-                        Some(res) => highlight_def(sema, krate, Definition::from(res)),
-                        None => HlTag::None.into(),
-                    }
-                }
+            match sema.resolve_derive_ident(&ast::Ident::cast(token).unwrap()) {
+                Some(res) => highlight_def(sema, krate, Definition::from(res)),
                 None => HlTag::None.into(),
             }
         }

crates/ide_db/src/defs.rs

@@ -17,7 +17,7 @@ use syntax::{
     match_ast, AstToken, SyntaxKind, SyntaxNode, SyntaxToken,
 };
 
-use crate::{helpers::try_resolve_derive_input, RootDatabase};
+use crate::RootDatabase;
 
 // FIXME: a more precise name would probably be `Symbol`?
 #[derive(Debug, PartialEq, Eq, Copy, Clone, Hash)]
@@ -55,11 +55,8 @@ impl Definition {
             let attr = ast::TokenTree::cast(parent.clone())
                 .and_then(|tt| tt.parent_meta())
                 .and_then(|meta| meta.parent_attr());
-            if let Some(attr) = attr {
-                return try_resolve_derive_input(&sema, &attr, &ident)
-                    .map(Into::into)
-                    .into_iter()
-                    .collect();
+            if let Some(_) = attr {
+                return sema.resolve_derive_ident(&ident).map(Into::into).into_iter().collect();
             }
         }
         Self::from_node(sema, &parent)

crates/ide_db/src/helpers.rs

@@ -74,26 +74,6 @@ pub fn get_path_at_cursor_in_tt(cursor: &ast::Ident) -> Option<ast::Path> {
         })
 }
 
-/// Parses and resolves the path at the cursor position in the given attribute, if it is a derive.
-/// This special case is required because the derive macro is a compiler builtin that discards the input derives.
-pub fn try_resolve_derive_input(
-    sema: &hir::Semantics<RootDatabase>,
-    attr: &ast::Attr,
-    cursor: &ast::Ident,
-) -> Option<PathResolution> {
-    let path = get_path_in_derive_attr(sema, attr, cursor)?;
-    let scope = sema.scope(attr.syntax());
-    // FIXME: This double resolve shouldn't be necessary
-    // It's only here so we prefer macros over other namespaces
-    match scope.speculative_resolve_as_mac(&path) {
-        Some(mac) if mac.kind() == hir::MacroKind::Derive => Some(PathResolution::Macro(mac)),
-        Some(_) => return None,
-        None => scope
-            .speculative_resolve(&path)
-            .filter(|res| matches!(res, PathResolution::Def(ModuleDef::Module(_)))),
-    }
-}
-
 /// Picks the token with the highest rank returned by the passed in function.
 pub fn pick_best_token(
     tokens: TokenAtOffset<SyntaxToken>,

crates/ide_db/src/helpers/import_assets.rs

@@ -146,6 +146,7 @@ impl ImportAssets {
         if let Some(_) = path.qualifier() {
             return None;
         }
+
         let name = NameToImport::exact_case_sensitive(path.segment()?.name_ref()?.to_string());
         let candidate_node = attr.syntax().clone();
         Some(Self {