Merge pull request #7277 from WalterBright/fix17955

fix Issue 17955 - compiler segfault in DsymbolSemanticVisitor::visit(…
merged-on-behalf-of: Iain Buclaw <ibuclaw@gdcproject.org>

src/ddmd/dclass.d

@@ -894,7 +894,7 @@ extern (C++) class ClassDeclaration : AggregateDeclaration
             extern (C++) static int virtualSemantic(Dsymbol s, void* param)
             {
                 auto fd = s.isFuncDeclaration();
-                if (fd && !(fd.storage_class & STCstatic))
+                if (fd && !(fd.storage_class & STCstatic) && !fd.isUnitTestDeclaration())
                     fd.dsymbolSemantic(null);
                 return 0;
             }

test/fail_compilation/fail17955.d

@@ -0,0 +1,84 @@
+// https://issues.dlang.org/show_bug.cgi?id=17955
+
+alias Alias(alias a) = a;
+
+template isISOExtStringSerializable(T)
+{
+    enum isISOExtStringSerializable = T.fromISOExtString("");
+}
+
+template RedisObjectCollection(){}
+
+struct RedisStripped(T, bool strip_id = true)
+{
+    alias unstrippedMemberIndices = indicesOf!(Select!(strip_id,
+            isRedisTypeAndNotID, isRedisType), T.tupleof);
+}
+
+template indicesOf(alias PRED, T...)
+{
+    template impl(size_t i)
+    {
+        static if (PRED!T)
+            impl TypeTuple;
+    }
+
+    alias indicesOf = impl!0;
+}
+
+template isRedisType(alias F)
+{
+    enum isRedisType = toRedis!(typeof(F));
+}
+
+template isRedisTypeAndNotID(){}
+
+string toRedis(T)()
+{
+    static if (isISOExtStringSerializable!T)
+        return;
+}
+
+struct User
+{
+    SysTime resetCodeExpireTime;
+}
+
+class RedisUserManController
+{
+    RedisObjectCollection!(RedisStripped!User) m_users;
+}
+
+class TimeZone
+{
+    abstract bool hasDST();
+}
+
+class SimpleTimeZone : TimeZone
+{
+    unittest {}
+
+    immutable(SimpleTimeZone) fromISOExtString(S)(S)
+    {
+        new SimpleTimeZone;
+    }
+}
+
+struct SysTime
+{
+
+    static fromISOExtString(S)(S)
+    {
+        dstring zoneStr;
+
+        try
+            SimpleTimeZone.fromISOExtString(zoneStr);
+
+        catch DateTimeException;
+    }
+}
+
+template Select(bool condition, T...)
+{
+    alias Select = Alias!(T[condition]);
+}