Summary:
We don't need a side table in ASTContext to hold CXXDefaultArgExprs. The
important part of building the CXXDefaultArgExprs was to ODR use the
default argument expressions, not to make AST nodes. Refactor the code
to only check the default argument, and remove the side table in
ASTContext which wasn't being serialized.
Fixes PR31121
Reviewers: thakis, rsmith, majnemer
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D27007
llvm-svn: 287774
Reid Kleckner