Summary:
For types deduced from typedef's and typeof's, don't warn for duplicate
declaration specifiers in C90 unless -pedantic.
Create a third diagnostic type for duplicate declaration specifiers.
Previously, we had an ExtWarn and a Warning. This change adds a third,
Extension, which only warns when -pedantic is set, staying silent
otherwise.
Fixes PR32985.
Reviewers: rsmith
Reviewed By: rsmith
Subscribers: srhines, cfe-commits
Differential Revision: https://reviews.llvm.org/D52849
llvm-svn: 343740