[weld-dev] Odd type assignability test

[Laird Nelson]

On Mon, Apr 27, 2020 at 5:38 AM Martin Kouba <mkouba at redhat.com> wrote:

> I think that you're right. Foo<E> is basically Foo<E extends Object> and
> according to the rules String is assignable to Object.


Just to be clear, this test (that I added temporarily to CovariantTypesTest
and ran just to make sure) fails (as I'd expect):

@Test
public <E> void testFooStringAssignableFromFooE() {
    Type a = new TypeLiteral<Foo<String>>() {
    }.getType();
    Type b = new TypeLiteral<Foo<E>>() {
    }.getType();
    assertTrue(CovariantTypes.isAssignableFrom(a, b)); // kaboom
}

But this test (the one under discussion) in BeanTypeAssignabilityRules
succeeds (obviously or Weld's test suite would be broken):

@Test
public <E> void testStringFooMatchesVariableFoo() throws Exception {
    Type stringFooType = new TypeLiteral<Foo<String>>() {
    }.getType();
    Type variableFooType = new TypeLiteral<Foo<E>>() {
    }.getType();
    Assert.assertTrue("Foo<String> should match Foo<E>",
getRules().matches(stringFooType, variableFooType));
}

So the rules CDI uses to do type matching (represented by
BeanTypeAssignabilityRules) are deliberately different from those used by
JLS (represented by CovariantTypes), right?

Best,
Laird
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/weld-dev/attachments/20200427/9d2a06f3/attachment.html