// If e is a FunctionExpression or ArrowFunctionExpression with no type parameters and no parameter or return type annotations, and T is a function type with EXACTLY ONE non - generic call signature, then any inferences made for type parameters referenced by the parameters of T’s call signature are fixed(section 4.12.2) and e is processed with the contextual type T, as described in section 4.9.3.
// If e is a FunctionExpression or ArrowFunctionExpression with no type parameters and no parameter or return type annotations, and T is a function type with EXACTLY ONE non - generic call signature, then any inferences made for type parameters referenced by the parameters of T’s call signature are fixed(section 4.12.2) and e is processed with the contextual type T, as described in section 4.9.3.