diff --git a/clang/lib/Sema/IdentifierResolver.cpp b/clang/lib/Sema/IdentifierResolver.cpp
--- a/clang/lib/Sema/IdentifierResolver.cpp
+++ b/clang/lib/Sema/IdentifierResolver.cpp
@@ -121,7 +121,10 @@
       // of the controlled statement.
       //
       assert(S->getParent() && "No TUScope?");
-      if (S->getParent()->getFlags() & Scope::ControlScope) {
+      // If the current decl is in a lambda, we shouldn't consider this is a
+      // redefinition as lambda has its own scope.
+      if (S->getParent()->getFlags() & Scope::ControlScope &&
+          !S->isFunctionScope()) {
         S = S->getParent();
         if (S->isDeclScope(D))
           return true;
diff --git a/clang/test/SemaCXX/cxx1z-init-statement.cpp b/clang/test/SemaCXX/cxx1z-init-statement.cpp
--- a/clang/test/SemaCXX/cxx1z-init-statement.cpp
+++ b/clang/test/SemaCXX/cxx1z-init-statement.cpp
@@ -90,3 +90,18 @@
   static_assert(constexpr_switch_init(-2) == 0, "");
   static_assert(constexpr_switch_init(-5) == -1, "");
 }
+
+int test_lambda_init() {
+  if (int x = []() {int x = 42; return x; }(); x) {
+  };
+
+  switch (int y = []() {int y = 42; return y; }(); y) {
+  case 42:
+    return 1;
+  }
+
+  for (int x = [] { int x = 0; return x; }();;)
+    ;
+
+  return 0;
+}