diff --git a/internal/gcimporter/gcimporter_test.go b/internal/gcimporter/gcimporter_test.go
index b93cd2a7c7f..95cc36c4d96 100644
--- a/internal/gcimporter/gcimporter_test.go
+++ b/internal/gcimporter/gcimporter_test.go
@@ -190,7 +190,6 @@ func TestImportTypeparamTests(t *testing.T) {
 			"nested.go":     "fails to compile",              // TODO(rfindley): investigate this.
 			"issue47631.go": "can not handle local type declarations",
 			"issue55101.go": "fails to compile",
-			"issue50259.go": "compiler crashes if GODEBUG=gotypesalias=1", // TODO(adonovan): delete when #66550 is fixed.
 		}
 	}
 
diff --git a/internal/gcimporter/iexport_go118_test.go b/internal/gcimporter/iexport_go118_test.go
index 3aed235a7f8..c748fb36165 100644
--- a/internal/gcimporter/iexport_go118_test.go
+++ b/internal/gcimporter/iexport_go118_test.go
@@ -123,12 +123,6 @@ func TestImportTypeparamTests(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			// TODO(adonovan): delete when #66550 is fixed.
-			if strings.Contains(os.Getenv("GODEBUG"), "gotypesalias=1") &&
-				entry.Name() == "issue50259.go" {
-				t.Skip("Skipping test of defined<->alias cycle under gotypesaliases=1 (#66550)")
-			}
-
 			if !bytes.HasPrefix(src, []byte("// run")) && !bytes.HasPrefix(src, []byte("// compile")) {
 				// We're bypassing the logic of run.go here, so be conservative about
 				// the files we consider in an attempt to make this test more robust to