fix Issue 17451 - ICE in ddmd/declaration.d(2179)

src/ddmd/declaration.d

@@ -2172,7 +2172,7 @@ extern (C++) class VarDeclaration : Declaration
         if (tv.ty == Tstruct)
         {
             StructDeclaration sd = (cast(TypeStruct)tv).sym;
-            if (!sd.dtor)
+            if (!sd.dtor || sd.errors)
                 return null;
 
             const sz = type.size();

test/fail_compilation/test17451.d

@@ -0,0 +1,45 @@
+/* TEST_OUTPUT:
+---
+fail_compilation/test17451.d(22): Error: undefined identifier `allocator`
+fail_compilation/test17451.d(23): Error: `long` has no effect in expression `false`
+fail_compilation/test17451.d(30): Error: variable test17451.HashMap!(ThreadSlot).HashMap.__lambda2.v size of type ThreadSlot is invalid
+fail_compilation/test17451.d(44): Error: template instance test17451.HashMap!(ThreadSlot) error instantiating
+---
+*/
+
+// https://issues.dlang.org/show_bug.cgi?id=17451
+
+interface ManualEvent {}
+
+interface EventDriver {
+        ManualEvent createManualEvent() ;
+}
+
+struct ArraySet(Key)
+{
+        ~this()
+    {
+                try allocator;
+                catch false; // should never happen
+        }
+}
+
+struct HashMap(TValue)
+{
+        alias Value = TValue;
+        static if ({ Value v; }) {}
+}
+
+struct Task {}
+
+class Libevent2Driver : EventDriver {
+        Libevent2ManualEvent createManualEvent() {}
+}
+
+struct ThreadSlot {
+        ArraySet!Task tasks;
+}
+
+class Libevent2ManualEvent {
+        HashMap!ThreadSlot m_waiters;
+}