[FUSE] Component attribute nameof()

[chsienki]

This PR changes the way we emit component parameter names in runtime to use nameof(ParameterName) rather than a string. This allows things like Find All References to work in the IDE as we have an actual reference to the parameter.

Note that this is technically a breaking change if a user has a method called nameof( that is in scope to the generated component. This was discussed previously and decided to be an appropriate trade off. If we still feel strongly about this, we could a) add a specific razor error for that case, or b) ship an analyzer that identifies it (see also: 9369a14#r1037660470)

There are still a couple of edge cases around bind-[get/set] that aren't handled by this as it seemed big enough already. I'll submit those in a follow up PR.

I strongly suggest reviewing commit-by-commit.

Fixes: #10403

[chsienki]

@dotnet/razor-compiler for reviews please :)

[jaredpar]

Do we have tests for situations like this

@using TheirComponent=Test.MyComponent;

<TheirComponent @bind-Value=""ParentValue"" />
@code {
    public int ParentValue { get; set; } = 42;

    public string nameof(string s) => string.Empty;
}");

[chsienki]

Sadly, this isn't supported today anyway: #7670

But I would expect it to work when we do. We get the containing type name from the actual roslyn INamedTypeSymbol so we would already have had to do de-aliasing at that point and have the real name in hand.

[jaredpar]

Sadly, this isn't supported today anyway: #7670

Locally it compiled fine on my machine. What am I missing?

[chsienki]

It'll compile, but you should get a warning warning RZ10012: Found markup element with unexpected name 'TheirComponent'. If this is intended to be a component, add a @using directive for its namespace.

You can write the using, and it even looks like it should work, but our tag helper discovery logic doesn't consider aliases, so it won't find it.

[jaredpar]

Trying to think about all the quirky behavior with nameof and how it could intersect with this feature.

Ensure nameof doesn't bind to a keyword.

public class @int : ComponentBase
{
    [Parameter]
    public bool BoolParameter { get; set; }
}

<int BoolParameter="true" />

nameof(dynamic) cannot bind to the type dynamic (late bound type) but can bind to other types named dynamic.

public class dynamic : ComponentBase
{
    [Parameter]
    public bool BoolParameter { get; set; }
}

<dynamic BoolParameter="true" />

Note: all of these samples compile today.

[chsienki]

Both @int and dynamic work as expected. Added tests to verify.

[333fred]

What if the type is in the global namespace?

[chsienki]

This is broken already today :(

#10609

[chsienki]

But I think it should work right? The attribute must always be on some kind of type, and while the type itself might not have a namespace we're not constructing that part, that's handled by roslyn for us.

[chsienki]

Yeah, so the issue is actually only with @bind- syntax. Components in top level namespaces work otherwise. Confirmed it's not an issue here and added a test to cover it.

[chsienki]

Integration test failure is unrelated to these changes. @dotnet/razor-compiler for reviews please :)

[jjonescz]

So we need to do a coordinated insertion per the note above?