diff --git a/clang/include/clang/AST/ComputeDependence.h b/clang/include/clang/AST/ComputeDependence.h
--- a/clang/include/clang/AST/ComputeDependence.h
+++ b/clang/include/clang/AST/ComputeDependence.h
@@ -131,7 +131,7 @@
 ExprDependence computeDependence(ImplicitValueInitExpr *E);
 ExprDependence computeDependence(InitListExpr *E);
 ExprDependence computeDependence(ExtVectorElementExpr *E);
-ExprDependence computeDependence(BlockExpr *E);
+ExprDependence computeDependence(BlockExpr *E, bool ContainsError);
 ExprDependence computeDependence(AsTypeExpr *E);
 ExprDependence computeDependence(DeclRefExpr *E, const ASTContext &Ctx);
 ExprDependence computeDependence(RecoveryExpr *E);
diff --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
--- a/clang/include/clang/AST/Expr.h
+++ b/clang/include/clang/AST/Expr.h
@@ -5974,9 +5974,9 @@
 protected:
   BlockDecl *TheBlock;
 public:
-  BlockExpr(BlockDecl *BD, QualType ty)
+  BlockExpr(BlockDecl *BD, QualType ty, bool ContainsError = false)
       : Expr(BlockExprClass, ty, VK_PRValue, OK_Ordinary), TheBlock(BD) {
-    setDependence(computeDependence(this));
+    setDependence(computeDependence(this, ContainsError));
   }
 
   /// Build an empty block expression.
diff --git a/clang/lib/AST/ComputeDependence.cpp b/clang/lib/AST/ComputeDependence.cpp
--- a/clang/lib/AST/ComputeDependence.cpp
+++ b/clang/lib/AST/ComputeDependence.cpp
@@ -252,10 +252,12 @@
   return E->getBase()->getDependence();
 }
 
-ExprDependence clang::computeDependence(BlockExpr *E) {
+ExprDependence clang::computeDependence(BlockExpr *E, bool ContainsError) {
   auto D = toExprDependenceForImpliedType(E->getType()->getDependence());
   if (E->getBlockDecl()->isDependentContext())
     D |= ExprDependence::Instantiation;
+  if ((D & ExprDependence::Value) && ContainsError)
+    D |= ExprDependence::Error;
   return D;
 }
 
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -16746,7 +16746,11 @@
   AnalysisBasedWarnings::Policy WP = AnalysisWarnings.getDefaultPolicy();
   PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo(&WP, BD, BlockTy);
 
-  BlockExpr *Result = new (Context) BlockExpr(BD, BlockTy);
+  bool ContainsError = llvm::any_of(BSI->Returns, [](const ReturnStmt *Return) {
+    const auto *RetValExpr = Return->getRetValue();
+    return RetValExpr && RetValExpr->containsErrors();
+  });
+  BlockExpr *Result = new (Context) BlockExpr(BD, BlockTy, ContainsError);
 
   // If the block isn't obviously global, i.e. it captures anything at
   // all, then we need to do a few things in the surrounding context:
diff --git a/clang/test/SemaObjC/crash-on-val-dep-block-expr.m b/clang/test/SemaObjC/crash-on-val-dep-block-expr.m
new file mode 100644
--- /dev/null
+++ b/clang/test/SemaObjC/crash-on-val-dep-block-expr.m
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -fblocks -fsyntax-only -verify %s
+// no crash
+
+int (^a)() = ^() {
+  return c; // expected-error {{use of undeclared identifier 'c'}}
+};
+
+int (^b)() = (^() {
+  return c; // expected-error {{use of undeclared identifier 'c'}}
+});