==== tests/cases/compiler/genericMergedDeclarationUsingTypeParameter.ts (3 errors) ====
    function foo<T extends U, U>(y: T, z: U) { return y; }
                 ~~~~~~~~~~~
!!! Constraint of a type parameter cannot reference any type parameter from the same type parameter list.
    module foo {
        export var x: T;
                      ~
!!! Cannot find name 'T'.
        var y = <T>1;
                 ~
!!! Cannot find name 'T'.
    }