C89 allowed a type specifier to be elided with the resulting type being
int, aka implicit int behavior. This feature was subsequently removed
in C99 without a deprecation period, so implementations continued to
support the feature. Now, as with implicit function declarations, is a
good time to reevaluate the need for this support.
This patch allows -Wimplicit-int to issue warnings in C89 mode (off by
default), defaults the warning to an error in C99 through C17, and
disables support for the feature entirely in C2x. It also removes a
warning about missing declaration specifiers that really was just an
implicit int warning in disguise and other minor related cleanups.
The code pattern used to implement the token rewriting hack doesn't
interact well with token caching in the pre-processor. As a result,
clang would crash on 'int f(::(id));' while doing a tenative parse of
the contents of the outer parentheses. The original code from PR11852
still doesn't crash the compiler.
This error recovery also often does the wrong thing with member function
pointers. The test case from the original PR doesn't recover the right
way either:
void S::(*pf)() = S::f; // should be 'void (S::*pf)()'
Instead we were recovering as 'void S::*pf()', which is still wrong.
If we still think that users mistakenly parenthesize identifiers in
nested name specifiers, we should change clang to intentionally parse
that form with an error, rather than doing a token rewrite.
Fixes PR26623, but I think there will be many more bugs like this around
token rewriting in the parser.
Reviewers: rsmith, rtrieu
Differential Revision: https://reviews.llvm.org/D25882
llvm-svn: 289273
We've decided to make the core rewriter class and PP rewriters mandatory.
They're only a few hundred lines of code in total and not worth supporting as a
distinct build configuration, especially since doing so disables key compiler
features.
This reverts commit r213150.
Revert "clang/test: Introduce the feature "rewriter" for --enable-clang-rewriter."
This reverts commit r213148.
Revert "Move clang/test/Frontend/rewrite-*.c to clang/test/Frontend/Rewriter/"
This reverts commit r213146.
llvm-svn: 213159
Aaron Ballman