cmd/compile/internal/types2: add a test for argument error unwrapping

This CL is a clean port of CL 351338 from go/types to types2.

Change-Id: I7fd0e5a447bf51cb359e71731c2f9b95e3960da6
Reviewed-on: https://go-review.googlesource.com/c/go/+/364536
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>

diff --git a/src/cmd/compile/internal/types2/api_test.go b/src/cmd/compile/internal/types2/api_test.go
index 7ec10638436fb595a417f7de77c66b2bd0b8d275..ca90e6b97d409fe47904a874becf2dca82501681 100644 (file)
--- a/src/cmd/compile/internal/types2/api_test.go
+++ b/src/cmd/compile/internal/types2/api_test.go
@@ -2014,6 +2014,20 @@ func TestInstantiateErrors(t *testing.T) {
        }
 }
 
+func TestArgumentErrorUnwrapping(t *testing.T) {
+       var err error = &ArgumentError{
+               Index: 1,
+               Err:   Error{Msg: "test"},
+       }
+       var e Error
+       if !errors.As(err, &e) {
+               t.Fatalf("error %v does not wrap types.Error", err)
+       }
+       if e.Msg != "test" {
+               t.Errorf("e.Msg = %q, want %q", e.Msg, "test")
+       }
+}
+
 func TestInstanceIdentity(t *testing.T) {
        imports := make(testImporter)
        conf := Config{Importer: imports}