run Typing_check_decls.fun_ on lambdas, too
Summary:
`Typing_check_decls` check types at definition sites, most notably if a type application `Foo<Bar>` satisfies the constraints on Foo's parameter. In the context of higher-kinded types, `Typing_check_decls` will also initiate a well-kindedness check on the involved types.
Currently, `Typing_check_decls` is not called on lambdas. This means that for instance the parameter types of a lambda may violate type constraints. The `violated_constraints.php` test I added is accepted without errors before my change.
Reviewed By: andrewjkennedy
Differential Revision:
D22982346
fbshipit-source-id:
1ecbe39f880f2323a6a30a45a5e649a0f9bf747e