llvm-capstone/clang/test/Parser/c1x-generic-selection.c
Richard Smith c90e198107 Fix parsing of enum-base to follow C++11 rules.
Previously we implemented non-standard disambiguation rules to
distinguish an enum-base from a bit-field but otherwise treated a :
after an elaborated-enum-specifier as introducing an enum-base. That
misparses various examples (anywhere an elaborated-type-specifier can
appear followed by a colon, such as within a ternary operator or
_Generic).

We now implement the C++11 rules, with the old cases accepted as
extensions where that seemed reasonable. These amount to:
 * an enum-base must always be accompanied by an enum definition (except
   in a standalone declaration of the form 'enum E : T;')
 * in a member-declaration, 'enum E :' always introduces an enum-base,
   never a bit-field
 * in a type-specifier (or similar context), 'enum E :' is not
   permitted; the colon means whatever else it would mean in that
   context.

Fixed underlying types for enums are also permitted in Objective-C and
under MS extensions, plus as a language extension in all other modes.
The behavior in ObjC and MS extensions modes is unchanged (but the
bit-field disambiguation is a bit better); remaining language modes
follow the C++11 rules.

Fixes PR45726, PR39979, PR19810, PR44941, and most of PR24297, plus C++
core issues 1514 and 1966.
2020-05-08 19:32:00 -07:00

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C

// RUN: %clang_cc1 -std=c1x -fsyntax-only -verify %s
void foo(void) {
_Generic; // expected-error {{expected '('}}
(void) _Generic(0); // expected-error {{expected ','}}
(void) _Generic(0, void); // expected-error {{expected ':'}}
(void) _Generic(0,
default: 0, // expected-note {{previous default generic association is here}}
default: 0); // expected-error {{duplicate default generic association}}
}
enum E { e };
int bar(int n) {
// PR45726
return _Generic(0, enum E: n, default: 0);
}
int baz(int n) {
// PR39979
return _Generic(0, enum { e }: n, default: 0);
}