fix: instance method cannot inherit class generic (#2166)

[HerrCai0907]

⯈For class instance method, ctxtypes should use class generic type instead of context. So override is more reasonable.

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[dcodeIO]

Iirc the check was there for situations like

class Foo<T> {
  bar<T>() { baz<T>(); } // here
}
function baz<U>() { ... }

where contextual types of the method take precedence over the class's. Before I merge, can you confirm that this case isn't regressing? :)

[HerrCai0907]

Iirc the check was there for situations like

class Foo<T> {
  bar<T>() { baz<T>(); } // here
}
function baz<U>() { ... }

where contextual types of the method take precedence over the class's. Before I merge, can you confirm that this case isn't regressing? :)

The result is OK, I add them into test.
After overridden by class generic, ctxtype will be overridden by function generic type again. see below code.

    // override whatever is contextual with actual function type arguments
    var signatureNode = prototype.functionTypeNode;
    var typeParameterNodes = prototype.typeParameterNodes;
    var numFunctionTypeArguments: i32;
    if (typeArguments !== null && (numFunctionTypeArguments = typeArguments.length) > 0) {
      assert(typeParameterNodes !== null && numFunctionTypeArguments == typeParameterNodes.length);
      for (let i = 0; i < numFunctionTypeArguments; ++i) {
        ctxTypes.set(
          (<TypeParameterNode[]>typeParameterNodes)[i].name.text,
          typeArguments[i]
        );
      }
    } else {
      assert(!typeParameterNodes || typeParameterNodes.length == 0);
    }

They ctxtype process flow is like that:

• maybeInferCall will infer generic of fn by outside function type (T-1) . In this step, class generic should not be used.
• resolveFunction will override context type with class generic of instance method (T-2) and then override it again with fn generic types which are inferred in step1.

So it seems like matching the expectations.

function testfunc2166<T-1>(): void {
  let a = new Test2166Ref1<string>();
  // class generic should override non-related function generic(testfunc2166): T in fn is string
  a.fn("11", 1);
}
class Test2166Ref1<T-2> {
  fn<U>(a1: T, a2: U): void {
  }
}
testfunc2166<i64>();

[dcodeIO]

Makes sense, thanks. Good to now have a test case as well :)