The previous code made the assumption that the ASTScope for a variable
declaration should be the one of the declaration's source location. That is not
necessarily the case, in some cases it should be an ancestor scope. This patch
introduces a map from ValueDecl -> ASTScope that is derived from querying each
ASTScope for its locals, which matches also what happens in name lookup. This
patch also fixes the nesting of SILDebugScopes created for guard statement
bodies, which are incorrectly nested in the ASTScope hierarchy.
rdar://108940570
An expression macro can expand not just to code inside the function, but also to
a closure. Such a closure needs to be treated similar to any functions generated
from a freestanding macro: Its instructions should have locations that point
straight into the macro buffer. Instructions that are expanded into the same
function as the macro expansion can be represented using inline locations
pointing back to the macro expansion, but this is not an option for top-level
function declaration.
https://github.com/apple/swift/issues/65484
rdar://108618562
inside closures while type checking a macro expansion.
PreCheckExpr, ConstraintGenerator, and other walkers do not walk into macro
expansions. However, the implementation of this macro walking behavior in
ASTWalker would skip any declaration that appears inside any macro expansion
buffer. This is incorrect for cases where the parent is in the same macro
expansion buffer, because the local declaration is not inside a new macro
expansion. This caused bogus errors when type checking expanded macro expressions
containing closures with local declarations, because pre-check and constraint
generation mistakenly skipped local pattern bindings.
