This reverts commit bb16ee049d,
reversing changes made to a8d831f5f5.
It's not sufficient to solve the problem, and the choices were to do
something more complicated, or just take a simple brute force
approach. We're going with the latter.
Replace two prominent uses of SubstitutionList, in ConcreteDeclRef and
Witness, with SubstitutionMap. Deal with the myriad places where we
now have substitution maps and need substitution lists (or vice versa)
caused by this change.
Overall, removes ~50 explicit uses of SubstitutionList (of ~400).
Convert NameAliasType’s internal representation from tail-allocating an
array of Substitutions (to be treated as a SubstitutionList) to store a
single SubstitutionMap. Serialize using that SubstitutionMap.
Allow substitution maps to be serialized directly (via an ID), writing out
the replacement types and conformances as appropriate. This is a more
efficient form of serialization than the current SubstitutionList approach,
because it maintains uniqueness of substitution maps within a module file,
and is a step toward eliminating SubstitutionList entirely.
Absence of synthetic generic environment should not affect
serialization of the required substitutions because they can
come from outer requirement context for static members.
Resolves: rdar://problem/36497404
We should always go through the Clang importer to reinstantiate them. Serializing them leads to the possibility of us ending up with multiple conformances with different identities that ought to be equivalent.
We should always go through the Clang importer to reinstantiate them. Serializing them leads to the possibility of us ending up with multiple conformances with different identities that ought to be equivalent.
Add serialization layouts for rare instructions that take extra attributes. We
can continue adding bits to these layout without affecting the layout of the
vast majority of instructions.
We still use the old layout for NameAliasType for builtin types, so
rename the Layout struct and corresponding code to describe its new
(more restricted) purpose.
Introduce a new Type node, BoundNameAliasType, which describes a
reference to a typealias that requires substitutions to produce the
underlying type. This new type node is used both for references to
generic typealiases and for references to (non-generic) typealiases
that occur within generic contexts, e.g., Array<Int>.Element.
At present, the new type node is mainly useful in preserving type
sugar for diagnostics purposes, as well as being reflected in other
tools (indexing, code completion, etc.). The intent is to completely
replace NameAliasType in the future.
