Merge #9810

9810: Add reference here r=matklad a=ivan770

Superseds #6853 

Co-authored-by: ivan770 <ivan@ivan770.me>

crates/ide_diagnostics/src/handlers/add_reference_here.rs

@@ -0,0 +1,163 @@
+use hir::db::AstDatabase;
+use ide_db::source_change::SourceChange;
+use syntax::AstNode;
+use text_edit::TextEdit;
+
+use crate::{fix, Assist, Diagnostic, DiagnosticsContext};
+
+// Diagnostic: add-reference-here
+//
+// This diagnostic is triggered when there's a missing referencing of expression.
+pub(crate) fn add_reference_here(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::AddReferenceHere,
+) -> Diagnostic {
+    Diagnostic::new(
+        "add-reference-here",
+        "add reference here",
+        ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range,
+    )
+    .with_fixes(fixes(ctx, d))
+}
+
+fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::AddReferenceHere) -> Option<Vec<Assist>> {
+    let root = ctx.sema.db.parse_or_expand(d.expr.file_id)?;
+    let arg_expr = d.expr.value.to_node(&root);
+
+    let arg_with_ref = format!("&{}{}", d.mutability.as_keyword_for_ref(), arg_expr.syntax());
+
+    let arg_range = arg_expr.syntax().text_range();
+    let edit = TextEdit::replace(arg_range, arg_with_ref);
+    let source_change =
+        SourceChange::from_text_edit(d.expr.file_id.original_file(ctx.sema.db), edit);
+
+    Some(vec![fix("add_reference_here", "Add reference here", source_change, arg_range)])
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_diagnostics, check_fix};
+
+    #[test]
+    fn missing_reference() {
+        check_diagnostics(
+            r#"
+fn main() {
+    test(123);
+       //^^^ 💡 error: add reference here
+}
+fn test(arg: &i32) {}
+"#,
+        );
+    }
+
+    #[test]
+    fn test_add_reference_to_int() {
+        check_fix(
+            r#"
+fn main() {
+    test(123$0);
+}
+fn test(arg: &i32) {}
+            "#,
+            r#"
+fn main() {
+    test(&123);
+}
+fn test(arg: &i32) {}
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_add_mutable_reference_to_int() {
+        check_fix(
+            r#"
+fn main() {
+    test($0123);
+}
+fn test(arg: &mut i32) {}
+            "#,
+            r#"
+fn main() {
+    test(&mut 123);
+}
+fn test(arg: &mut i32) {}
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_add_reference_to_array() {
+        check_fix(
+            r#"
+fn main() {
+    test($0[1, 2, 3]);
+}
+fn test(arg: &[i32]) {}
+            "#,
+            r#"
+fn main() {
+    test(&[1, 2, 3]);
+}
+fn test(arg: &[i32]) {}
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_add_reference_to_method_call() {
+        check_fix(
+            r#"
+fn main() {
+    Test.call_by_ref($0123);
+}
+struct Test;
+impl Test {
+    fn call_by_ref(&self, arg: &i32) {}
+}
+            "#,
+            r#"
+fn main() {
+    Test.call_by_ref(&123);
+}
+struct Test;
+impl Test {
+    fn call_by_ref(&self, arg: &i32) {}
+}
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_add_reference_to_let_stmt() {
+        check_fix(
+            r#"
+fn main() {
+    let test: &i32 = $0123;
+}
+            "#,
+            r#"
+fn main() {
+    let test: &i32 = &123;
+}
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_add_mutable_reference_to_let_stmt() {
+        check_fix(
+            r#"
+fn main() {
+    let test: &mut i32 = $0123;
+}
+            "#,
+            r#"
+fn main() {
+    let test: &mut i32 = &mut 123;
+}
+            "#,
+        );
+    }
+}

crates/ide_diagnostics/src/lib.rs

@@ -24,6 +24,7 @@
 //! don't yet have a great pattern for how to do them properly.
 
 mod handlers {
+    pub(crate) mod add_reference_here;
     pub(crate) mod break_outside_of_loop;
     pub(crate) mod inactive_code;
     pub(crate) mod incorrect_case;
@@ -176,6 +177,7 @@ pub fn diagnostics(
     for diag in diags {
         #[rustfmt::skip]
         let d = match diag {
+            AnyDiagnostic::AddReferenceHere(d) => handlers::add_reference_here::add_reference_here(&ctx, &d),
             AnyDiagnostic::BreakOutsideOfLoop(d) => handlers::break_outside_of_loop::break_outside_of_loop(&ctx, &d),
             AnyDiagnostic::IncorrectCase(d) => handlers::incorrect_case::incorrect_case(&ctx, &d),
             AnyDiagnostic::MacroError(d) => handlers::macro_error::macro_error(&ctx, &d),