Correctly highlight ranges of diagnostics from macros

closes #2799

5 files changed, 89 insertions, 21 deletions

diff --git a/crates/ra_hir/src/semantics.rs b/crates/ra_hir/src/semantics.rs
index 2707e422d..0b477f0e9 100644
--- a/crates/ra_hir/src/semantics.rs
+++ b/crates/ra_hir/src/semantics.rs
@@ -20,6 +20,7 @@ use rustc_hash::{FxHashMap, FxHashSet};
 
 use crate::{
     db::HirDatabase,
+    diagnostics::Diagnostic,
     semantics::source_to_def::{ChildContainer, SourceToDefCache, SourceToDefCtx},
     source_analyzer::{resolve_hir_path, SourceAnalyzer},
     AssocItem, Function, HirFileId, ImplDef, InFile, Local, MacroDef, Module, ModuleDef, Name,
@@ -126,6 +127,13 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         original_range(self.db, node.as_ref())
     }
 
+    pub fn diagnostics_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
+        let src = diagnostics.source();
+        let root = self.db.parse_or_expand(src.file_id).unwrap();
+        let node = src.value.to_node(&root);
+        original_range(self.db, src.with_value(&node))
+    }
+
     pub fn ancestors_with_macros(&self, node: SyntaxNode) -> impl Iterator<Item = SyntaxNode> + '_ {
         let node = self.find_file(node);
         node.ancestors_with_macros(self.db).map(|it| it.value)
diff --git a/crates/ra_hir_def/src/diagnostics.rs b/crates/ra_hir_def/src/diagnostics.rs
index dbaf4deef..2ee28fbaa 100644
--- a/crates/ra_hir_def/src/diagnostics.rs
+++ b/crates/ra_hir_def/src/diagnostics.rs
@@ -20,11 +20,11 @@ impl Diagnostic for UnresolvedModule {
     fn message(&self) -> String {
         "unresolved module".to_string()
     }
-    fn highlight_range(&self) -> TextRange {
-        self.highlight_range
+    fn highlight_range(&self) -> InFile<TextRange> {
+        InFile::new(self.file, self.highlight_range)
     }
     fn source(&self) -> InFile<SyntaxNodePtr> {
-        InFile { file_id: self.file, value: self.decl.clone().into() }
+        InFile::new(self.file, self.decl.clone().into())
     }
     fn as_any(&self) -> &(dyn Any + Send + 'static) {
         self
diff --git a/crates/ra_hir_expand/src/diagnostics.rs b/crates/ra_hir_expand/src/diagnostics.rs
index 714e700f7..813fbf0e2 100644
--- a/crates/ra_hir_expand/src/diagnostics.rs
+++ b/crates/ra_hir_expand/src/diagnostics.rs
@@ -22,7 +22,7 @@ use crate::{db::AstDatabase, InFile};
 
 pub trait Diagnostic: Any + Send + Sync + fmt::Debug + 'static {
     fn message(&self) -> String;
-    fn highlight_range(&self) -> TextRange;
+    fn highlight_range(&self) -> InFile<TextRange>;
     fn source(&self) -> InFile<SyntaxNodePtr>;
     fn as_any(&self) -> &(dyn Any + Send + 'static);
 }
diff --git a/crates/ra_hir_ty/src/diagnostics.rs b/crates/ra_hir_ty/src/diagnostics.rs
index da85bd082..018c2ad3f 100644
--- a/crates/ra_hir_ty/src/diagnostics.rs
+++ b/crates/ra_hir_ty/src/diagnostics.rs
@@ -21,12 +21,12 @@ impl Diagnostic for NoSuchField {
         "no such field".to_string()
     }
 
-    fn highlight_range(&self) -> TextRange {
-        self.highlight_range
+    fn highlight_range(&self) -> InFile<TextRange> {
+        InFile::new(self.file, self.highlight_range)
     }
 
     fn source(&self) -> InFile<SyntaxNodePtr> {
-        InFile { file_id: self.file, value: self.field.clone().into() }
+        InFile::new(self.file, self.field.clone().into())
     }
 
     fn as_any(&self) -> &(dyn Any + Send + 'static) {
@@ -50,8 +50,8 @@ impl Diagnostic for MissingFields {
         }
         buf
     }
-    fn highlight_range(&self) -> TextRange {
-        self.highlight_range
+    fn highlight_range(&self) -> InFile<TextRange> {
+        InFile::new(self.file, self.highlight_range)
     }
 
     fn source(&self) -> InFile<SyntaxNodePtr> {
@@ -88,8 +88,8 @@ impl Diagnostic for MissingPatFields {
         }
         buf
     }
-    fn highlight_range(&self) -> TextRange {
-        self.highlight_range
+    fn highlight_range(&self) -> InFile<TextRange> {
+        InFile::new(self.file, self.highlight_range)
     }
     fn source(&self) -> InFile<SyntaxNodePtr> {
         InFile { file_id: self.file, value: self.field_list.clone().into() }
@@ -111,8 +111,8 @@ impl Diagnostic for MissingMatchArms {
     fn message(&self) -> String {
         String::from("Missing match arm")
     }
-    fn highlight_range(&self) -> TextRange {
-        self.highlight_range
+    fn highlight_range(&self) -> InFile<TextRange> {
+        InFile::new(self.file, self.highlight_range)
     }
     fn source(&self) -> InFile<SyntaxNodePtr> {
         InFile { file_id: self.file, value: self.match_expr.clone().into() }
@@ -133,8 +133,8 @@ impl Diagnostic for MissingOkInTailExpr {
     fn message(&self) -> String {
         "wrap return expression in Ok".to_string()
     }
-    fn highlight_range(&self) -> TextRange {
-        self.highlight_range
+    fn highlight_range(&self) -> InFile<TextRange> {
+        InFile::new(self.file, self.highlight_range)
     }
     fn source(&self) -> InFile<SyntaxNodePtr> {
         InFile { file_id: self.file, value: self.expr.clone().into() }
diff --git a/crates/ra_ide/src/diagnostics.rs b/crates/ra_ide/src/diagnostics.rs
index 901ad104c..e7e201709 100644
--- a/crates/ra_ide/src/diagnostics.rs
+++ b/crates/ra_ide/src/diagnostics.rs
@@ -1,4 +1,8 @@
-//! FIXME: write short doc here
+//! Collects diagnostics & fixits  for a single file.
+//!
+//! The tricky bit here is that diagnostics are produced by hir in terms of
+//! macro-expanded files, but we need to present them to the users in terms of
+//! original files. So we need to map the ranges.
 
 use std::cell::RefCell;
 
@@ -46,7 +50,7 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
     let mut sink = DiagnosticSink::new(|d| {
         res.borrow_mut().push(Diagnostic {
             message: d.message(),
-            range: d.highlight_range(),
+            range: sema.diagnostics_range(d).range,
             severity: Severity::Error,
             fix: None,
         })
@@ -62,7 +66,7 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
         let create_file = FileSystemEdit::CreateFile { source_root, path };
         let fix = SourceChange::file_system_edit("create module", create_file);
         res.borrow_mut().push(Diagnostic {
-            range: d.highlight_range(),
+            range: sema.diagnostics_range(d).range,
             message: d.message(),
             severity: Severity::Error,
             fix: Some(fix),
@@ -95,7 +99,7 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
         };
 
         res.borrow_mut().push(Diagnostic {
-            range: d.highlight_range(),
+            range: sema.diagnostics_range(d).range,
             message: d.message(),
             severity: Severity::Error,
             fix,
@@ -103,7 +107,7 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
     })
     .on::<hir::diagnostics::MissingMatchArms, _>(|d| {
         res.borrow_mut().push(Diagnostic {
-            range: d.highlight_range(),
+            range: sema.diagnostics_range(d).range,
             message: d.message(),
             severity: Severity::Error,
             fix: None,
@@ -115,7 +119,7 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
         let edit = TextEdit::replace(node.syntax().text_range(), replacement);
         let fix = SourceChange::source_file_edit_from("wrap with ok", file_id, edit);
         res.borrow_mut().push(Diagnostic {
-            range: d.highlight_range(),
+            range: sema.diagnostics_range(d).range,
             message: d.message(),
             severity: Severity::Error,
             fix: Some(fix),
@@ -622,6 +626,62 @@ mod tests {
     }
 
     #[test]
+    fn range_mapping_out_of_macros() {
+        let (analysis, file_id) = single_file(
+            r"
+            fn some() {}
+            fn items() {}
+            fn here() {}
+
+            macro_rules! id {
+                ($($tt:tt)*) => { $($tt)*};
+            }
+
+            fn main() {
+                let _x = id![Foo { a: 42 }];
+            }
+
+            pub struct Foo {
+                pub a: i32,
+                pub b: i32,
+            }
+        ",
+        );
+        let diagnostics = analysis.diagnostics(file_id).unwrap();
+        assert_debug_snapshot!(diagnostics, @r###"
+        [
+            Diagnostic {
+                message: "Missing structure fields:\n- b",
+                range: [224; 233),
+                fix: Some(
+                    SourceChange {
+                        label: "fill struct fields",
+                        source_file_edits: [
+                            SourceFileEdit {
+                                file_id: FileId(
+                                    1,
+                                ),
+                                edit: TextEdit {
+                                    atoms: [
+                                        AtomTextEdit {
+                                            delete: [3; 9),
+                                            insert: "{a:42, b: ()}",
+                                        },
+                                    ],
+                                },
+                            },
+                        ],
+                        file_system_edits: [],
+                        cursor_position: None,
+                    },
+                ),
+                severity: Error,
+            },
+        ]
+        "###);
+    }
+
+    #[test]
     fn test_check_unnecessary_braces_in_use_statement() {
         check_not_applicable(
             "