Fix too early specification of generic types (#1130)

Author: Frotty

de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/translation/imtranslation/EliminateGenerics.java

@@ -582,12 +582,12 @@ public void visit(ImTypeArgument ta) {
             @Override
             public void visit(ImNull e) {
                 ImType newT = transformType(e.getType(), generics, typeVars);
-                newT = specializeType(newT);
                 e.setType(newT);
 
                 ImExpr safe = specializeNullInitializer(e, newT);
                 if (safe != e) {
                     e.replaceBy(safe);
+                    return;
                 }
                 super.visit(e);
             }

de.peeeq.wurstscript/src/test/java/tests/wurstscript/tests/GenericsWithTypeclassesTests.java

@@ -2023,5 +2023,35 @@ public void fullArrayListTest() throws IOException {
         testAssertOkFileWithStdLib(new File(TEST_DIR + "arrayList.wurst"), true);
     }
 
+    @Test
+    public void genericNullComparison() {
+        testAssertOkLinesWithStdLib(true,
+            "package test",
+            "import NoWurst",
+            "import ClosureTimers",
+            "native testSuccess()",
+            "public class Reference<T:>",
+            "    T val",
+            "    construct(T val)",
+            "        this.val = val",
+            "    function into() returns T",
+            "        let rval = val",
+            "        destroy this",
+            "        return rval",
+            "",
+            "var r = new Reference(0.0)",
+            "",
+            "init",
+            "    // force member access on the global",
+            "    doAfter(.1) ->",
+            "       r.val = 1.0",
+            "       if r != null and not r == null and r.into() == 1.0",
+            "           testSuccess()",
+            "    testSuccess() // to make compiler happy",
+            "endpackage"
+        );
+    }
+
+
 
 }