diff --git a/clang/lib/AST/Interp/ByteCodeExprGen.cpp b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
--- a/clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -588,12 +588,18 @@
 }
 
 template <class Emitter> bool ByteCodeExprGen<Emitter>::discard(const Expr *E) {
+  if (E->containsErrors())
+    return false;
+
   OptionScope<Emitter> Scope(this, /*NewDiscardResult=*/true);
   return this->Visit(E);
 }
 
 template <class Emitter>
 bool ByteCodeExprGen<Emitter>::visit(const Expr *E) {
+  if (E->containsErrors())
+    return false;
+
   OptionScope<Emitter> Scope(this, /*NewDiscardResult=*/false);
   return this->Visit(E);
 }
@@ -1156,6 +1162,7 @@
 /// We need to evaluate the initializer and return its value.
 template <class Emitter>
 bool ByteCodeExprGen<Emitter>::visitDecl(const VarDecl *VD) {
+  assert(!VD->isInvalidDecl() && "Trying to constant evaluate an invalid decl");
   std::optional<PrimType> VarT = classify(VD->getType());
 
   // Create and initialize the variable.
diff --git a/clang/test/AST/Interp/functions.cpp b/clang/test/AST/Interp/functions.cpp
--- a/clang/test/AST/Interp/functions.cpp
+++ b/clang/test/AST/Interp/functions.cpp
@@ -84,3 +84,18 @@
   return 5;
 }
 static_assert(a() == 5, "");
+
+constexpr int invalid() {
+  // Invalid expression in visit().
+  while(huh) {} // expected-error {{use of undeclared identifier}} \
+                // ref-error {{use of undeclared identifier}}
+
+  return 0;
+}
+
+constexpr void invalid2() {
+  int i = 0;
+  // Invalid expression in discard().
+  huh(); // expected-error {{use of undeclared identifier}} \
+         // ref-error {{use of undeclared identifier}}
+}