give type mismatch hint when checker fails for same value but wrong type

.gitignore

@@ -1 +1,2 @@
 .vscode
+.idea

checker_test.go

@@ -62,6 +62,7 @@ type OuterJSON struct {
 }
 
 type boolean bool
+type myString string
 
 var checkerTests = []struct {
 	about                 string
@@ -179,6 +180,19 @@ got:
 want:
   "42"
 `,
+}, {
+	about:   "Equals: string and named string type with same value",
+	checker: qt.Equals,
+	got:     "hello",
+	args:    []interface{}{myString("hello")},
+	expectedCheckFailure: `
+error:
+  values are not equal
+got:
+  "hello"
+want:
+  quicktest_test.myString("hello")
+`,
 }, {
 	about:   "Equals: nil and nil",
 	checker: qt.Equals,

format.go

@@ -46,6 +46,14 @@ func Format(v interface{}) string {
 		// (json.RawMessage for example).
 		return fmt.Sprintf("%T(%s)", v, quoteString(string(bytes)))
 	}
+	// Handle named string types (e.g. type myString string) explicitly so that
+	// the type name is included in the output. Without this they fall through to
+	// pretty.Formatter which renders them as a plain quoted string, identical to
+	// a plain string value, causing the deduplication in the reporter to
+	// incorrectly print "<same as got>" when the types differ.
+	if rv := reflect.ValueOf(v); rv.IsValid() && rv.Kind() == reflect.String {
+		return fmt.Sprintf("%T(%s)", v, quoteString(rv.String()))
+	}
 	// The pretty.Sprint equivalent does not quote string values.
 	return fmt.Sprintf("%# v", pretty.Formatter(v))
 }