diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -4983,7 +4983,9 @@
         !EvaluateDecl(Info, SS->getConditionVariable()))
       return ESR_Failed;
     if (SS->getCond()->isValueDependent()) {
-      if (!EvaluateDependentExpr(SS->getCond(), Info))
+      // Stop evaluate if condition expression contains errors.
+      if (SS->getCond()->containsErrors() ||
+          !EvaluateDependentExpr(SS->getCond(), Info))
         return ESR_Failed;
     } else {
       if (!EvaluateInteger(SS->getCond(), Value, Info))
diff --git a/clang/test/SemaCXX/switch.cpp b/clang/test/SemaCXX/switch.cpp
--- a/clang/test/SemaCXX/switch.cpp
+++ b/clang/test/SemaCXX/switch.cpp
@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++17 %s
 
 void test() {
   bool x = true;
@@ -146,3 +147,17 @@
 }
 
 } // namespace EmptyEnum
+
+#if __cplusplus >= 201703L
+constexpr int foo(unsigned char c) {
+    switch (unknown_value) { // expected-error {{use of undeclared identifier}}
+    case 0:
+        return 7;
+    default:
+        break;
+    }
+    return 0;
+}
+
+static_assert(foo('d')); // expected-error {{static assertion expression is not an integral constant expression}}
+#endif