8 files changed, 112 insertions, 30 deletions

diff --git a/crates/hir/src/code_model.rs b/crates/hir/src/code_model.rs
index 19ea26e36..c134356ef 100644
--- a/crates/hir/src/code_model.rs
+++ b/crates/hir/src/code_model.rs
@@ -257,34 +257,22 @@ impl ModuleDef {
     }
 
     pub fn diagnostics(self, db: &dyn HirDatabase, sink: &mut DiagnosticSink) {
-        match self {
+        let id = match self {
             ModuleDef::Adt(it) => match it {
-                Adt::Struct(it) => {
-                    hir_ty::diagnostics::validate_module_item(db, it.id.into(), sink)
-                }
-                Adt::Enum(it) => hir_ty::diagnostics::validate_module_item(db, it.id.into(), sink),
-                Adt::Union(it) => hir_ty::diagnostics::validate_module_item(db, it.id.into(), sink),
+                Adt::Struct(it) => it.id.into(),
+                Adt::Enum(it) => it.id.into(),
+                Adt::Union(it) => it.id.into(),
             },
-            ModuleDef::Trait(it) => {
-                hir_ty::diagnostics::validate_module_item(db, it.id.into(), sink)
-            }
-            ModuleDef::Function(it) => {
-                hir_ty::diagnostics::validate_module_item(db, it.id.into(), sink)
-            }
-            ModuleDef::TypeAlias(it) => {
-                hir_ty::diagnostics::validate_module_item(db, it.id.into(), sink)
-            }
-            ModuleDef::Module(it) => {
-                hir_ty::diagnostics::validate_module_item(db, it.id.into(), sink)
-            }
-            ModuleDef::Const(it) => {
-                hir_ty::diagnostics::validate_module_item(db, it.id.into(), sink)
-            }
-            ModuleDef::Static(it) => {
-                hir_ty::diagnostics::validate_module_item(db, it.id.into(), sink)
-            }
+            ModuleDef::Trait(it) => it.id.into(),
+            ModuleDef::Function(it) => it.id.into(),
+            ModuleDef::TypeAlias(it) => it.id.into(),
+            ModuleDef::Module(it) => it.id.into(),
+            ModuleDef::Const(it) => it.id.into(),
+            ModuleDef::Static(it) => it.id.into(),
             _ => return,
-        }
+        };
+
+        hir_ty::diagnostics::validate_module_item(db, id, sink)
     }
 }
 
@@ -389,6 +377,8 @@ impl Module {
         let crate_def_map = db.crate_def_map(self.id.krate);
         crate_def_map.add_diagnostics(db.upcast(), self.id.local_id, sink);
         for decl in self.declarations(db) {
+            decl.diagnostics(db, sink);
+
             match decl {
                 crate::ModuleDef::Function(f) => f.diagnostics(db, sink),
                 crate::ModuleDef::Module(m) => {
diff --git a/crates/hir/src/diagnostics.rs b/crates/hir/src/diagnostics.rs
index 363164b9b..da2b40849 100644
--- a/crates/hir/src/diagnostics.rs
+++ b/crates/hir/src/diagnostics.rs
@@ -2,5 +2,6 @@
 pub use hir_def::diagnostics::UnresolvedModule;
 pub use hir_expand::diagnostics::{Diagnostic, DiagnosticSink, DiagnosticSinkBuilder};
 pub use hir_ty::diagnostics::{
-    MismatchedArgCount, MissingFields, MissingMatchArms, MissingOkInTailExpr, NoSuchField,
+    IncorrectCase, MismatchedArgCount, MissingFields, MissingMatchArms, MissingOkInTailExpr,
+    NoSuchField,
 };
diff --git a/crates/hir_ty/src/diagnostics.rs b/crates/hir_ty/src/diagnostics.rs
index bd370e3b2..66762b90e 100644
--- a/crates/hir_ty/src/diagnostics.rs
+++ b/crates/hir_ty/src/diagnostics.rs
@@ -298,7 +298,7 @@ impl Diagnostic for IncorrectCase {
     }
 
     fn is_experimental(&self) -> bool {
-        true
+        false
     }
 }
 
diff --git a/crates/ide/src/diagnostics.rs b/crates/ide/src/diagnostics.rs
index f5d627b6e..71ab98c1f 100644
--- a/crates/ide/src/diagnostics.rs
+++ b/crates/ide/src/diagnostics.rs
@@ -96,6 +96,9 @@ pub(crate) fn diagnostics(
         .on::<hir::diagnostics::NoSuchField, _>(|d| {
             res.borrow_mut().push(diagnostic_with_fix(d, &sema));
         })
+        .on::<hir::diagnostics::IncorrectCase, _>(|d| {
+            res.borrow_mut().push(warning_with_fix(d, &sema));
+        })
         // Only collect experimental diagnostics when they're enabled.
         .filter(|diag| !(diag.is_experimental() && config.disable_experimental))
         .filter(|diag| !config.disabled.contains(diag.code().as_str()));
@@ -130,6 +133,16 @@ fn diagnostic_with_fix<D: DiagnosticWithFix>(d: &D, sema: &Semantics<RootDatabas
     }
 }
 
+fn warning_with_fix<D: DiagnosticWithFix>(d: &D, sema: &Semantics<RootDatabase>) -> Diagnostic {
+    Diagnostic {
+        // name: Some(d.name().into()),
+        range: sema.diagnostics_display_range(d).range,
+        message: d.message(),
+        severity: Severity::WeakWarning,
+        fix: d.fix(&sema),
+    }
+}
+
 fn check_unnecessary_braces_in_use_statement(
     acc: &mut Vec<Diagnostic>,
     file_id: FileId,
@@ -253,6 +266,37 @@ mod tests {
         );
     }
 
+    /// Similar to `check_fix`, but applies all the available fixes.
+    fn check_fixes(ra_fixture_before: &str, ra_fixture_after: &str) {
+        let after = trim_indent(ra_fixture_after);
+
+        let (analysis, file_position) = fixture::position(ra_fixture_before);
+        let diagnostic = analysis
+            .diagnostics(&DiagnosticsConfig::default(), file_position.file_id)
+            .unwrap()
+            .pop()
+            .unwrap();
+        let fix = diagnostic.fix.unwrap();
+        let target_file_contents = analysis.file_text(file_position.file_id).unwrap();
+        let actual = {
+            let mut actual = target_file_contents.to_string();
+            // Go from the last one to the first one, so that ranges won't be affected by previous edits.
+            for edit in fix.source_change.source_file_edits.iter().rev() {
+                edit.edit.apply(&mut actual);
+            }
+            actual
+        };
+
+        assert_eq_text!(&after, &actual);
+        assert!(
+            fix.fix_trigger_range.start() <= file_position.offset
+                && fix.fix_trigger_range.end() >= file_position.offset,
+            "diagnostic fix range {:?} does not touch cursor position {:?}",
+            fix.fix_trigger_range,
+            file_position.offset
+        );
+    }
+
     /// Checks that a diagnostic applies to the file containing the `<|>` cursor marker
     /// which has a fix that can apply to other files.
     fn check_apply_diagnostic_fix_in_other_file(ra_fixture_before: &str, ra_fixture_after: &str) {
@@ -790,4 +834,24 @@ struct Foo {
         let diagnostics = analysis.diagnostics(&DiagnosticsConfig::default(), file_id).unwrap();
         assert!(!diagnostics.is_empty());
     }
+
+    #[test]
+    fn test_rename_incorrect_case() {
+        check_fixes(
+            r#"
+pub struct test_struct<|> { one: i32 }
+
+pub fn some_fn(val: test_struct) -> test_struct {
+    test_struct { one: val.one + 1 }
+}
+"#,
+            r#"
+pub struct TestStruct { one: i32 }
+
+pub fn some_fn(val: TestStruct) -> TestStruct {
+    TestStruct { one: val.one + 1 }
+}
+"#,
+        );
+    }
 }
diff --git a/crates/ide/src/diagnostics/fixes.rs b/crates/ide/src/diagnostics/fixes.rs
index 68ae1c239..286ef0785 100644
--- a/crates/ide/src/diagnostics/fixes.rs
+++ b/crates/ide/src/diagnostics/fixes.rs
@@ -3,7 +3,10 @@
 use base_db::FileId;
 use hir::{
     db::AstDatabase,
-    diagnostics::{Diagnostic, MissingFields, MissingOkInTailExpr, NoSuchField, UnresolvedModule},
+    diagnostics::{
+        Diagnostic, IncorrectCase, MissingFields, MissingOkInTailExpr, NoSuchField,
+        UnresolvedModule,
+    },
     HasSource, HirDisplay, Semantics, VariantDef,
 };
 use ide_db::{
@@ -17,7 +20,7 @@ use syntax::{
 };
 use text_edit::TextEdit;
 
-use crate::diagnostics::Fix;
+use crate::{diagnostics::Fix, references::rename::rename_with_semantics, FilePosition};
 
 /// A [Diagnostic] that potentially has a fix available.
 ///
@@ -99,6 +102,19 @@ impl DiagnosticWithFix for MissingOkInTailExpr {
     }
 }
 
+impl DiagnosticWithFix for IncorrectCase {
+    fn fix(&self, sema: &Semantics<RootDatabase>) -> Option<Fix> {
+        let file_id = self.file.original_file(sema.db);
+        let offset = self.ident.text_range().start();
+        let file_position = FilePosition { file_id, offset };
+
+        let rename_changes = rename_with_semantics(sema, file_position, &self.suggested_text)?;
+
+        let label = format!("Rename to {}", self.suggested_text);
+        Some(Fix::new(&label, rename_changes.info, rename_changes.range))
+    }
+}
+
 fn missing_record_expr_field_fix(
     sema: &Semantics<RootDatabase>,
     usage_file_id: FileId,
diff --git a/crates/ide/src/references.rs b/crates/ide/src/references.rs
index f65a05ea3..88e2f2db3 100644
--- a/crates/ide/src/references.rs
+++ b/crates/ide/src/references.rs
@@ -9,7 +9,7 @@
 //! at the index that the match starts at and its tree parent is
 //! resolved to the search element definition, we get a reference.
 
-mod rename;
+pub(crate) mod rename;
 
 use hir::Semantics;
 use ide_db::{
diff --git a/crates/ide/src/references/rename.rs b/crates/ide/src/references/rename.rs
index f3b5cfc8c..f9a11e43d 100644
--- a/crates/ide/src/references/rename.rs
+++ b/crates/ide/src/references/rename.rs
@@ -42,7 +42,14 @@ pub(crate) fn rename(
     new_name: &str,
 ) -> Result<RangeInfo<SourceChange>, RenameError> {
     let sema = Semantics::new(db);
+    rename_with_semantics(&sema, position, new_name)
+}
 
+pub(crate) fn rename_with_semantics(
+    sema: &Semantics<RootDatabase>,
+    position: FilePosition,
+    new_name: &str,
+) -> Result<RangeInfo<SourceChange>, RenameError> {
     match lex_single_syntax_kind(new_name) {
         Some(res) => match res {
             (SyntaxKind::IDENT, _) => (),
diff --git a/crates/syntax/src/ptr.rs b/crates/syntax/src/ptr.rs
index d3fb7a5d9..34e20464a 100644
--- a/crates/syntax/src/ptr.rs
+++ b/crates/syntax/src/ptr.rs
@@ -23,6 +23,10 @@ impl SyntaxNodePtr {
         SyntaxNodePtr { range: node.text_range(), kind: node.kind() }
     }
 
+    pub fn text_range(&self) -> TextRange {
+        self.range.clone()
+    }
+
     pub fn to_node(&self, root: &SyntaxNode) -> SyntaxNode {
         assert!(root.parent().is_none());
         successors(Some(root.clone()), |node| {