fix: autofix for missing wrapped unit in return expr

Author: roife

src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/type_mismatch.rs

@@ -130,6 +130,7 @@ fn add_missing_ok_or_some(
 if d.actual.is_unit(){
 ifletExpr::BlockExpr(block) = &expr {
 if block.tail_expr().is_none(){
+// Fix for forms like `fn foo() -> Result<(), String> {}`
 letmut builder = TextEdit::builder();
 let block_indent = block.indent_level();
 
@@ -156,6 +157,20 @@ fn add_missing_ok_or_some(
  acc.push(fix("insert_wrapped_unit",&name, source_change, expr_range));
 }
 returnSome(());
+}elseifletExpr::ReturnExpr(ret_expr) = &expr {
+// Fix for forms like `fn foo() -> Result<(), String> { return; }`
+if ret_expr.expr().is_none(){
+letmut builder = TextEdit::builder();
+ builder
+.insert(ret_expr.syntax().text_range().end(),format!(" {variant_name}(())"));
+let source_change = SourceChange::from_text_edit(
+ expr_ptr.file_id.original_file(ctx.sema.db),
+ builder.finish(),
+);
+let name = format!("Insert {variant_name}(()) as the return value");
+ acc.push(fix("insert_wrapped_unit",&name, source_change, expr_range));
+}
+returnSome(());
 }
 }
 
@@ -603,6 +618,29 @@ fn foo() -> Result<(), ()> {
 );
 }
 
+#[test]
+fntest_wrapped_unit_as_return_expr(){
+check_fix(
+r#"
+//- minicore: result
+fn foo(b: bool) -> Result<(), String> {
+ if b {
+ return$0;
+ }
+
+ Err("oh dear".to_owned())
+}"#,
+r#"
+fn foo(b: bool) -> Result<(), String> {
+ if b {
+ return Ok(());
+ }
+
+ Err("oh dear".to_owned())
+}"#,
+);
+}
+
 #[test]
 fntest_in_const_and_static(){
 check_fix(