From 53ddeffe9d13c0a4ca34e299ae807d5e25d87197 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bastian=20M=C3=BCller?= <bastian@axiomzen.co>
Date: Tue, 16 Nov 2021 15:35:00 -0800
Subject: [PATCH] fix regression introduced in a250336: gracefully handle
 invalid restrictions

---
 runtime/sema/checker.go                   |  4 ++++
 runtime/tests/checker/restriction_test.go | 14 ++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/runtime/sema/checker.go b/runtime/sema/checker.go
index 770021328a..2b80bba90e 100644
--- a/runtime/sema/checker.go
+++ b/runtime/sema/checker.go
@@ -1141,6 +1141,10 @@ func (checker *Checker) convertRestrictedType(t *ast.RestrictedType) Type {
 					Range: ast.NewRangeFromPositioned(restriction),
 				})
 			}
+
+			// NOTE: ignore this invalid type
+			// and do not add it to the restrictions result
+			continue
 		}
 
 		restrictions = append(restrictions, restrictionInterfaceType)
diff --git a/runtime/tests/checker/restriction_test.go b/runtime/tests/checker/restriction_test.go
index 47e30b3867..4e3fa4e273 100644
--- a/runtime/tests/checker/restriction_test.go
+++ b/runtime/tests/checker/restriction_test.go
@@ -1124,3 +1124,17 @@ func TestCheckRestrictedConformance(t *testing.T) {
 
 	require.NoError(t, err)
 }
+
+func TestCheckInvalidRestriction(t *testing.T) {
+
+	t.Parallel()
+
+	_, err := ParseAndCheck(t, `
+      let x: {h} = nil
+    `)
+
+	errs := ExpectCheckerErrors(t, err, 2)
+
+	require.IsType(t, &sema.NotDeclaredError{}, errs[0])
+	require.IsType(t, &sema.AmbiguousRestrictedTypeError{}, errs[1])
+}