chore: change str_ref_to_string to str_ref_to_owned

ToString is implemented by many different types than &str, and
represents a serialization into string data. The fact that said data is
returned as owned, is an implementation detail.

If merely copying borrowed string data to owned string data is all that
is desired, ToOwned is a much better choice, because if the user later
refactors the code such that the input is no longer an `&str`, then they
will get a compiler error instead of a mysterious change-in-behavior.

Author: mmirate

crates/ide-diagnostics/src/handlers/type_mismatch.rs

@@ -35,7 +35,7 @@ fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::TypeMismatch) -> Option<Vec<Assi
     add_reference(ctx, d, &mut fixes);
     add_missing_ok_or_some(ctx, d, &mut fixes);
     remove_semicolon(ctx, d, &mut fixes);
-    str_ref_to_string(ctx, d, &mut fixes);
+    str_ref_to_owned(ctx, d, &mut fixes);
 
     if fixes.is_empty() {
         None
@@ -135,7 +135,7 @@ fn remove_semicolon(
     Some(())
 }
 
-fn str_ref_to_string(
+fn str_ref_to_owned(
     ctx: &DiagnosticsContext<'_>,
     d: &hir::TypeMismatch,
     acc: &mut Vec<Assist>,
@@ -151,12 +151,12 @@ fn str_ref_to_string(
     let expr = d.expr.value.to_node(&root);
     let expr_range = expr.syntax().text_range();
 
-    let to_string = format!(".to_string()");
+    let to_owned = format!(".to_owned()");
 
-    let edit = TextEdit::insert(expr.syntax().text_range().end(), to_string);
+    let edit = TextEdit::insert(expr.syntax().text_range().end(), to_owned);
     let source_change =
         SourceChange::from_text_edit(d.expr.file_id.original_file(ctx.sema.db), edit);
-    acc.push(fix("str_ref_to_string", "Add .to_string() here", source_change, expr_range));
+    acc.push(fix("str_ref_to_owned", "Add .to_owned() here", source_change, expr_range));
 
     Some(())
 }
@@ -527,7 +527,7 @@ fn foo() -> SomeOtherEnum { 0$0 }
     }
 
     #[test]
-    fn str_ref_to_string() {
+    fn str_ref_to_owned() {
         check_fix(
             r#"
 struct String;
@@ -540,7 +540,7 @@ fn test() -> String {
 struct String;
 
 fn test() -> String {
-    "a".to_string()
+    "a".to_owned()
 }
             "#,
         );