Fix nullability check (in case of explicitly nullable types constructed from ype variables)

compiler/backend/src/org/jetbrains/jet/codegen/CodegenUtil.java

@@ -286,9 +286,12 @@ public class CodegenUtil {
      * @return true if a value of this type can be null
      */
     public static boolean isNullableType(@NotNull JetType type) {
+        if (type.isNullable()) {
+            return true;
+        }
         if (type.getConstructor().getDeclarationDescriptor() instanceof TypeParameterDescriptor) {
             return TypeUtils.hasNullableSuperType(type);
         }
-        return type.isNullable();
+        return false;
     }
 }

compiler/testData/codegen/notNullAssertions/noAssertionForNullableGenericMethodCall.kt

@@ -0,0 +1,7 @@
+import java.util.HashMap
+
+class A<T: Any> {
+    fun main() {
+        HashMap<String, T>()[""]
+    }
+}

compiler/tests/org/jetbrains/jet/codegen/GenerateNotNullAssertionsTest.java

@@ -154,6 +154,14 @@ public class GenerateNotNullAssertionsTest extends CodegenTestCase {
         assertNoIntrinsicsMethodIsCalled(PackageClassUtils.getPackageClassName(FqName.ROOT));
     }
 
+    public void testNoAssertionForNullableGenericMethodCall() {
+        setUpEnvironment(true, false);
+
+        loadFile("notNullAssertions/noAssertionForNullableGenericMethodCall.kt");
+
+        assertNoIntrinsicsMethodIsCalled("A");
+    }
+
     private void assertNoIntrinsicsMethodIsCalled(String className) {
         ClassFileFactory classes = generateClassesInFile();
         ClassReader reader = new ClassReader(classes.asBytes(className + ".class"));