tests/cases/compiler/indexSignatureWithInitializer1.ts(2,4): error TS1020: An index signature parameter cannot have an initializer.
tests/cases/compiler/indexSignatureWithInitializer1.ts(2,4): error TS2371: A parameter initializer is only allowed in a function or constructor implementation.


==== tests/cases/compiler/indexSignatureWithInitializer1.ts (2 errors) ====
    class C {
      [a: number = 1]: number;
       ~
!!! error TS1020: An index signature parameter cannot have an initializer.
       ~~~~~~~~~~~~~
!!! error TS2371: A parameter initializer is only allowed in a function or constructor implementation.
    }