diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -2161,6 +2161,12 @@
     return getTypeInfo(cast<AdjustedType>(T)->getAdjustedType().getTypePtr());
   case Type::ObjCInterface: {
     const auto *ObjCI = cast<ObjCInterfaceType>(T);
+    if (ObjCI->getDecl()->isInvalidDecl()) {
+      // FIXME: are the numbers correct?
+      Width = 8;
+      Align = 8;
+      break;
+    }
     const ASTRecordLayout &Layout = getASTObjCInterfaceLayout(ObjCI->getDecl());
     Width = toBits(Layout.getSize());
     Align = toBits(Layout.getAlignment());
diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -3222,7 +3222,8 @@
   if (D->hasExternalLexicalStorage() && !D->getDefinition())
     getExternalSource()->CompleteType(const_cast<ObjCInterfaceDecl*>(D));
   D = D->getDefinition();
-  assert(D && D->isThisDeclarationADefinition() && "Invalid interface decl!");
+  assert(D && !D->isInvalidDecl() && D->isThisDeclarationADefinition() &&
+         "Invalid interface decl!");
 
   // Look up this layout, if already laid out, return what we have.
   const ObjCContainerDecl *Key =
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -16172,6 +16172,10 @@
                                 IdentifierInfo *FieldName,
                                 QualType FieldTy, bool IsMsStruct,
                                 Expr *BitWidth, bool *ZeroWidth) {
+  assert(BitWidth);
+  if (BitWidth->containsErrors())
+    return ExprError();
+
   // Default to true; that shouldn't confuse checks for emptiness
   if (ZeroWidth)
     *ZeroWidth = true;
diff --git a/clang/test/Sema/invalid-bitwidth-expr.cpp b/clang/test/Sema/invalid-bitwidth-expr.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/Sema/invalid-bitwidth-expr.cpp
@@ -0,0 +1,5 @@
+// RUN: %clang_cc1 -verify -fsyntax-only -frecovery-ast %s
+// RUN: %clang_cc1 -verify -fsyntax-only -fno-recovery-ast %s
+
+struct X { int Y: foo(); }; // expected-error {{use of undeclared identifier}}
+constexpr int ss = sizeof(X);
diff --git a/clang/test/Sema/invalid-bitwidth-expr.mm b/clang/test/Sema/invalid-bitwidth-expr.mm
new file mode 100644
--- /dev/null
+++ b/clang/test/Sema/invalid-bitwidth-expr.mm
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -fobjc-runtime=gcc -frecovery-ast -verify %s
+// RUN: %clang_cc1 -fobjc-runtime=gcc -fno-recovery-ast -verify %s
+@interface Ivar
+{
+  int Foo : foo(); // expected-error {{use of undeclared identifier}}
+};
+@end
+
+constexpr int s = sizeof(Ivar);