diff --git a/lldb/lit/Expr/Inputs/basic.cpp b/lldb/lit/Expr/Inputs/basic.cpp
new file mode 100644
index 000000000000..80a79379a2ec
--- /dev/null
+++ b/lldb/lit/Expr/Inputs/basic.cpp
@@ -0,0 +1,12 @@
+class Patatino {
+private:
+  long tinky;
+
+public:
+  Patatino(long tinky) { this->tinky = tinky; }
+};
+
+int main(void) {
+  Patatino *a = new Patatino(26);
+  return 0;
+}
diff --git a/lldb/lit/Expr/TestCallCppSym.test b/lldb/lit/Expr/TestCallCppSym.test
new file mode 100644
index 000000000000..ac48c6f5160a
--- /dev/null
+++ b/lldb/lit/Expr/TestCallCppSym.test
@@ -0,0 +1,6 @@
+# RUN: %cxx %p/Inputs/basic.cpp -g -o %t && %lldb -b -s %s -- %t 2>&1 | FileCheck %s
+
+breakpoint set --file basic.cpp --line 12
+run
+call (int)_Znwm(23)
+# CHECK: error: use of undeclared identifier '_Znwm'
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
index 07ff2e97aac7..093be6c898af 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
@@ -2072,6 +2072,15 @@ void ClangExpressionDeclMap::AddOneFunction(NameSearchContext &context,
       return;
     }
   } else if (symbol) {
+    // Don't insert a generic function decl for C++ symbol names.
+    // Creating a generic function decl is almost surely going to cause troubles
+    // as it breaks Clang/Sema invariants and causes crashes in clang while
+    // we're trying to evaluate the expression.
+    // This means users can't call C++ functions by mangled name when there
+    // are no debug info (as it happens for C symbol, e.g. printf()).
+    if (CPlusPlusLanguage::IsCPPMangledName(
+            symbol->GetMangled().GetMangledName().GetCString()))
+      return;
     fun_address = symbol->GetAddress();
     function_decl = context.AddGenericFunDecl();
     is_indirect_function = symbol->IsIndirect();