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2edb89c746
The C and C++ standards require the argument to __has_cpp_attribute and __has_c_attribute to be expanded ([cpp.cond]p5). It would make little sense to expand the argument to those operators but not expand the argument to __has_attribute and __has_declspec, so those were both also changed in this patch. Note that it might make sense for the other builtins to also expand their argument, but it wasn't as clear to me whether the behavior would be correct there, and so they were left for a future revision.
17 lines
991 B
C++
17 lines
991 B
C++
// RUN: %clang_cc1 -triple i386-unknown-unknown -Eonly -verify %s
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// We warn users if they write an attribute like
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// [[__clang__::fallthrough]] because __clang__ is a macro that expands to 1.
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// Instead, we suggest users use [[_Clang::fallthrough]] in this situation.
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// However, because __has_cpp_attribute (and __has_c_attribute) require
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// expanding their argument tokens, __clang__ expands to 1 in the feature test
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// macro as well. We don't currently give users a kind warning in this case,
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// but we previously did not expand macros and so this would return 0. Now that
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// we properly expand macros, users will now get an error about using incorrect
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// syntax.
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__has_cpp_attribute(__clang__::fallthrough) // expected-error {{missing ')' after <numeric_constant>}} \
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// expected-note {{to match this '('}} \
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// expected-error {{builtin feature check macro requires a parenthesized identifier}}
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