When wrapping a function which is supposed to capture the caller’s location, there’s always a risk that the wrapper won’t capture the information the wrapped function wants; for instance, you might pass `(…, line, column)` where the callee expected `(…, column, line)`.
This commit emits a warning when a call passes an explicit argument to something that has a default argument, and that explicit argument is itself a parameter with a default argument, and both parameters use magic identifiers, but they use *different* magic identifiers. This is partially in support of concise #file, but applies to all magic identifiers.
Fixes rdar://problem/58588633.
This commit changes how we represent caller-side
default arguments within the AST. Instead of
directly inserting them into the call-site, use
a DefaultArgumentExpr to refer to them indirectly.
The main goal of this change is to make it such
that the expression type-checker no longer cares
about the difference between caller-side and
callee-side default arguments. In particular, it
no longer cares about whether a caller-side
default argument is well-formed when type-checking
an apply. This is important because any
conversions introduced by the default argument
shouldn't affect the score of the resulting
solution.
Instead, caller-side defaults are now lazily
type-checked when we want to emit them in SILGen.
This is done through introducing a request, and
adjusting the logic in SILGen to be more lenient
with ErrorExprs. Caller-side defaults in primary
files are still also currently checked as a part
of the declaration by `checkDefaultArguments`.
Resolves SR-11085.
Resolves rdar://problem/56144412.
