Merge #5553

5553: Add fix ranges for diagnostics r=matklad a=SomeoneToIgnore

A follow-up of https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Fwg-rls-2.2E0/topic/Less.20red.20in.20the.20code

Now diagnostics can apply fixes in a range that's different from the range used to highlight the diagnostics.
Previous logic did not consider the fix range, having both ranges equal, which could cause a lot of red noise in the editor.
Now, the fix range gets used with the fix, the diagnostics range is used for everything else which allows to improve the error highlighting.

before:
<img width="191" alt="image" src="https://user-images.githubusercontent.com/2690773/88590727-df9a6a00-d063-11ea-97ed-9809c1c5e6e6.png">
after:
<img width="222" alt="image" src="https://user-images.githubusercontent.com/2690773/88590734-e1fcc400-d063-11ea-9b7c-25701cbd5352.png">

`MissingFields` and `MissingPatFields` diagnostics now have the fix range as `ast::RecordFieldList` of the expression with an error (as it was before this PR), and the diagnostics range as a `ast::Path` of the expression, if it's present (do you have any example of `ast::Expr::RecordLit` that has no path btw?).
The rest of the diagnostics have both ranges equal, same as it was before this PR.

Co-authored-by: Kirill Bulatov <[email protected]>

2 files changed, 7 insertions, 15 deletions

diff --git a/crates/ra_hir/src/diagnostics.rs b/crates/ra_hir/src/diagnostics.rs
index 266b513dc..363164b9b 100644
--- a/crates/ra_hir/src/diagnostics.rs
+++ b/crates/ra_hir/src/diagnostics.rs
@@ -1,8 +1,6 @@
 //! FIXME: write short doc here
 pub use hir_def::diagnostics::UnresolvedModule;
-pub use hir_expand::diagnostics::{
-    AstDiagnostic, Diagnostic, DiagnosticSink, DiagnosticSinkBuilder,
-};
+pub use hir_expand::diagnostics::{Diagnostic, DiagnosticSink, DiagnosticSinkBuilder};
 pub use hir_ty::diagnostics::{
     MismatchedArgCount, MissingFields, MissingMatchArms, MissingOkInTailExpr, NoSuchField,
 };
diff --git a/crates/ra_hir/src/semantics.rs b/crates/ra_hir/src/semantics.rs
index 872f5fa4c..36b688ccb 100644
--- a/crates/ra_hir/src/semantics.rs
+++ b/crates/ra_hir/src/semantics.rs
@@ -8,7 +8,7 @@ use hir_def::{
     resolver::{self, HasResolver, Resolver},
     AsMacroCall, FunctionId, TraitId, VariantId,
 };
-use hir_expand::{diagnostics::AstDiagnostic, hygiene::Hygiene, name::AsName, ExpansionInfo};
+use hir_expand::{hygiene::Hygiene, name::AsName, ExpansionInfo};
 use hir_ty::associated_type_shorthand_candidates;
 use itertools::Itertools;
 use ra_db::{FileId, FileRange};
@@ -110,13 +110,6 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.parse(file_id)
     }
 
-    pub fn ast<T: AstDiagnostic + Diagnostic>(&self, d: &T) -> <T as AstDiagnostic>::AST {
-        let file_id = d.source().file_id;
-        let root = self.db.parse_or_expand(file_id).unwrap();
-        self.imp.cache(root, file_id);
-        d.ast(self.db.upcast())
-    }
-
     pub fn expand(&self, macro_call: &ast::MacroCall) -> Option<SyntaxNode> {
         self.imp.expand(macro_call)
     }
@@ -146,8 +139,8 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.original_range(node)
     }
 
-    pub fn diagnostics_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
-        self.imp.diagnostics_range(diagnostics)
+    pub fn diagnostics_display_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
+        self.imp.diagnostics_display_range(diagnostics)
     }
 
     pub fn ancestors_with_macros(&self, node: SyntaxNode) -> impl Iterator<Item = SyntaxNode> + '_ {
@@ -389,10 +382,11 @@ impl<'db> SemanticsImpl<'db> {
         original_range(self.db, node.as_ref())
     }
 
-    fn diagnostics_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
-        let src = diagnostics.source();
+    fn diagnostics_display_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
+        let src = diagnostics.display_source();
         let root = self.db.parse_or_expand(src.file_id).unwrap();
         let node = src.value.to_node(&root);
+        self.cache(root, src.file_id);
         original_range(self.db, src.with_value(&node))
     }