For unresolved macros, hightlight only the last segment

crates/hir/src/diagnostics.rs

@@ -1,5 +1,7 @@
 //! FIXME: write short doc here
-pub use hir_def::diagnostics::{InactiveCode, UnresolvedModule, UnresolvedProcMacro};
+pub use hir_def::diagnostics::{
+    InactiveCode, UnresolvedMacroCall, UnresolvedModule, UnresolvedProcMacro,
+};
 pub use hir_expand::diagnostics::{
     Diagnostic, DiagnosticCode, DiagnosticSink, DiagnosticSinkBuilder,
 };

crates/hir/src/semantics.rs

@@ -16,13 +16,12 @@ use rustc_hash::{FxHashMap, FxHashSet};
 use syntax::{
     algo::find_node_at_offset,
     ast::{self, GenericParamsOwner, LoopBodyOwner},
-    match_ast, AstNode, SyntaxNode, SyntaxToken, TextSize,
+    match_ast, AstNode, SyntaxNode, SyntaxNodePtr, SyntaxToken, TextSize,
 };
 
 use crate::{
     code_model::Access,
     db::HirDatabase,
-    diagnostics::Diagnostic,
     semantics::source_to_def::{ChildContainer, SourceToDefCache, SourceToDefCtx},
     source_analyzer::{resolve_hir_path, SourceAnalyzer},
     AssocItem, Callable, ConstParam, Crate, Field, Function, HirFileId, Impl, InFile, Label,
@@ -141,7 +140,7 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.original_range(node)
     }
 
-    pub fn diagnostics_display_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
+    pub fn diagnostics_display_range(&self, diagnostics: InFile<SyntaxNodePtr>) -> FileRange {
         self.imp.diagnostics_display_range(diagnostics)
     }
 
@@ -385,8 +384,7 @@ impl<'db> SemanticsImpl<'db> {
         node.as_ref().original_file_range(self.db.upcast())
     }
 
-    fn diagnostics_display_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
-        let src = diagnostics.display_source();
+    fn diagnostics_display_range(&self, src: InFile<SyntaxNodePtr>) -> FileRange {
         let root = self.db.parse_or_expand(src.file_id).unwrap();
         let node = src.value.to_node(&root);
         self.cache(root, src.file_id);

crates/hir_def/src/body.rs

@@ -123,7 +123,7 @@ impl Expander {
             Some(it) => it,
             None => {
                 if err.is_none() {
-                    eprintln!("no error despite `as_call_id_with_errors` returning `None`");
+                    log::warn!("no error despite `as_call_id_with_errors` returning `None`");
                 }
                 return ExpandResult { value: None, err };
             }

crates/hir_def/src/diagnostics.rs

@@ -95,6 +95,34 @@ impl Diagnostic for UnresolvedImport {
     }
 }
 
+// Diagnostic: unresolved-macro-call
+//
+// This diagnostic is triggered if rust-analyzer is unable to resolove path to a
+// macro in a macro invocation.
+#[derive(Debug)]
+pub struct UnresolvedMacroCall {
+    pub file: HirFileId,
+    pub node: AstPtr<ast::MacroCall>,
+}
+
+impl Diagnostic for UnresolvedMacroCall {
+    fn code(&self) -> DiagnosticCode {
+        DiagnosticCode("unresolved-macro-call")
+    }
+    fn message(&self) -> String {
+        "unresolved macro call".to_string()
+    }
+    fn display_source(&self) -> InFile<SyntaxNodePtr> {
+        InFile::new(self.file, self.node.clone().into())
+    }
+    fn as_any(&self) -> &(dyn Any + Send + 'static) {
+        self
+    }
+    fn is_experimental(&self) -> bool {
+        true
+    }
+}
+
 // Diagnostic: inactive-code
 //
 // This diagnostic is shown for code with inactive `#[cfg]` attributes.

crates/hir_def/src/lib.rs

@@ -57,8 +57,10 @@ use std::{
 
 use base_db::{impl_intern_key, salsa, CrateId};
 use hir_expand::{
-    ast_id_map::FileAstId, eager::expand_eager_macro, hygiene::Hygiene, AstId, HirFileId, InFile,
-    MacroCallId, MacroCallKind, MacroDefId, MacroDefKind,
+    ast_id_map::FileAstId,
+    eager::{expand_eager_macro, ErrorEmitted},
+    hygiene::Hygiene,
+    AstId, HirFileId, InFile, MacroCallId, MacroCallKind, MacroDefId, MacroDefKind,
 };
 use la_arena::Idx;
 use nameres::DefMap;
@@ -592,8 +594,15 @@ impl AsMacroCall for InFile<&ast::MacroCall> {
             error_sink(mbe::ExpandError::Other("malformed macro invocation".into()));
         }
 
-        AstIdWithPath::new(ast_id.file_id, ast_id.value, path?)
-            .as_call_id_with_errors(db, krate, resolver, error_sink)
+        macro_call_as_call_id(
+            &AstIdWithPath::new(ast_id.file_id, ast_id.value, path?),
+            db,
+            krate,
+            resolver,
+            error_sink,
+        )
+        .ok()?
+        .ok()
     }
 }
 
@@ -610,61 +619,50 @@ impl<T: ast::AstNode> AstIdWithPath<T> {
     }
 }
 
-impl AsMacroCall for AstIdWithPath<ast::MacroCall> {
-    fn as_call_id_with_errors(
-        &self,
-        db: &dyn db::DefDatabase,
-        krate: CrateId,
-        resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
-        error_sink: &mut dyn FnMut(mbe::ExpandError),
-    ) -> Option<MacroCallId> {
-        let def: MacroDefId = resolver(self.path.clone()).or_else(|| {
-            error_sink(mbe::ExpandError::Other(format!("could not resolve macro `{}`", self.path)));
-            None
-        })?;
-
-        if let MacroDefKind::BuiltInEager(_) = def.kind {
-            let macro_call = InFile::new(self.ast_id.file_id, self.ast_id.to_node(db.upcast()));
-            let hygiene = Hygiene::new(db.upcast(), self.ast_id.file_id);
-
-            Some(
-                expand_eager_macro(
-                    db.upcast(),
-                    krate,
-                    macro_call,
-                    def,
-                    &|path: ast::Path| resolver(path::ModPath::from_src(path, &hygiene)?),
-                    error_sink,
-                )
-                .ok()?
-                .into(),
-            )
-        } else {
-            Some(def.as_lazy_macro(db.upcast(), krate, MacroCallKind::FnLike(self.ast_id)).into())
-        }
-    }
+struct UnresolvedMacro;
+
+fn macro_call_as_call_id(
+    call: &AstIdWithPath<ast::MacroCall>,
+    db: &dyn db::DefDatabase,
+    krate: CrateId,
+    resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
+    error_sink: &mut dyn FnMut(mbe::ExpandError),
+) -> Result<Result<MacroCallId, ErrorEmitted>, UnresolvedMacro> {
+    let def: MacroDefId = resolver(call.path.clone()).ok_or(UnresolvedMacro)?;
+
+    let res = if let MacroDefKind::BuiltInEager(_) = def.kind {
+        let macro_call = InFile::new(call.ast_id.file_id, call.ast_id.to_node(db.upcast()));
+        let hygiene = Hygiene::new(db.upcast(), call.ast_id.file_id);
+
+        expand_eager_macro(
+            db.upcast(),
+            krate,
+            macro_call,
+            def,
+            &|path: ast::Path| resolver(path::ModPath::from_src(path, &hygiene)?),
+            error_sink,
+        )
+        .map(MacroCallId::from)
+    } else {
+        Ok(def.as_lazy_macro(db.upcast(), krate, MacroCallKind::FnLike(call.ast_id)).into())
+    };
+    Ok(res)
 }
 
-impl AsMacroCall for AstIdWithPath<ast::Item> {
-    fn as_call_id_with_errors(
-        &self,
-        db: &dyn db::DefDatabase,
-        krate: CrateId,
-        resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
-        error_sink: &mut dyn FnMut(mbe::ExpandError),
-    ) -> Option<MacroCallId> {
-        let def: MacroDefId = resolver(self.path.clone()).or_else(|| {
-            error_sink(mbe::ExpandError::Other(format!("could not resolve macro `{}`", self.path)));
-            None
-        })?;
-
-        Some(
-            def.as_lazy_macro(
-                db.upcast(),
-                krate,
-                MacroCallKind::Attr(self.ast_id, self.path.segments().last()?.to_string()),
-            )
-            .into(),
+fn item_attr_as_call_id(
+    item_attr: &AstIdWithPath<ast::Item>,
+    db: &dyn db::DefDatabase,
+    krate: CrateId,
+    resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
+) -> Result<MacroCallId, UnresolvedMacro> {
+    let def: MacroDefId = resolver(item_attr.path.clone()).ok_or(UnresolvedMacro)?;
+    let last_segment = item_attr.path.segments().last().ok_or(UnresolvedMacro)?;
+    let res = def
+        .as_lazy_macro(
+            db.upcast(),
+            krate,
+            MacroCallKind::Attr(item_attr.ast_id, last_segment.to_string()),
         )
-    }
+        .into();
+    Ok(res)
 }

crates/hir_def/src/nameres.rs

@@ -417,6 +417,8 @@ mod diagnostics {
 
         UnresolvedProcMacro { ast: MacroCallKind },
 
+        UnresolvedMacroCall { ast: AstId<ast::MacroCall> },
+
         MacroError { ast: MacroCallKind, message: String },
     }
 
@@ -477,6 +479,13 @@ mod diagnostics {
             Self { in_module: container, kind: DiagnosticKind::MacroError { ast, message } }
         }
 
+        pub(super) fn unresolved_macro_call(
+            container: LocalModuleId,
+            ast: AstId<ast::MacroCall>,
+        ) -> Self {
+            Self { in_module: container, kind: DiagnosticKind::UnresolvedMacroCall { ast } }
+        }
+
         pub(super) fn add_to(
             &self,
             db: &dyn DefDatabase,
@@ -589,6 +598,11 @@ mod diagnostics {
                     });
                 }
 
+                DiagnosticKind::UnresolvedMacroCall { ast } => {
+                    let node = ast.to_node(db.upcast());
+                    sink.push(UnresolvedMacroCall { file: ast.file_id, node: AstPtr::new(&node) });
+                }
+
                 DiagnosticKind::MacroError { ast, message } => {
                     let (file, ast) = match ast {
                         MacroCallKind::FnLike(ast) => {