Aaron Ballman 2cb2cd242c Change the behavior of implicit int diagnostics
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.
2022-05-04 08:35:47 -04:00

123 lines
3.9 KiB
C

// RUN: %clang_cc1 %s -fsyntax-only -verify -verify=c2x -pedantic -Wno-strict-prototypes
// PR1892, PR11354
void f(double a[restrict][5]) { __typeof(a) x = 10; } // expected-warning {{(aka 'double (*restrict)[5]')}}
int foo (__const char *__path);
int foo(__const char *__restrict __file);
void func(const char*); // expected-note {{previous declaration is here}}
void func(char*); // expected-error{{conflicting types for 'func'}}
void g(int (*)(const void **, const void **));
void g(int (*compar)()) {
}
void h(); // expected-note {{previous declaration is here}}
void h (const char *fmt, ...) {} // expected-error{{conflicting types for 'h'}}
// PR1965
int t5(b); // expected-error {{parameter list without types}}
int t6(int x, g); // expected-error {{type specifier missing, defaults to 'int'}}
int t7(, ); // expected-error {{expected parameter declarator}} expected-error {{expected parameter declarator}}
int t8(, int a); // expected-error {{expected parameter declarator}}
int t9(int a, ); // expected-error {{expected parameter declarator}}
// PR2042
void t10(){}
void t11(){t10(1);} // expected-warning{{too many arguments}}
// PR3208
void t12(int) {} // c2x-warning{{omitting the parameter name in a function definition is a C2x extension}}
// PR2790
void t13() {
return 0; // expected-error {{void function 't13' should not return a value}}
}
int t14() {
return; // expected-error {{non-void function 't14' should return a value}}
}
// <rdar://problem/6097326>
y(y) { return y; } // expected-error{{parameter 'y' was not declared, defaults to 'int'; ISO C99 and later do not support implicit int}} \
// expected-error{{type specifier missing, defaults to 'int'}}
// PR3137, <rdar://problem/6127293>
extern int g0_3137(void);
void f0_3137() {
int g0_3137(void);
}
void f1_3137() {
int (*fp)(void) = g0_3137;
}
void f1static() {
static void f2static(int); // expected-error{{function declared in block scope cannot have 'static' storage class}}
register void f2register(int); // expected-error{{illegal storage class on function}}
}
struct incomplete_test a(void) {} // expected-error{{incomplete result type 'struct incomplete_test' in function definition}} \
// expected-note{{forward declaration of 'struct incomplete_test'}}
extern __inline
__attribute__((__gnu_inline__))
void gnu_inline1() {}
void
__attribute__((__gnu_inline__)) // expected-warning {{'gnu_inline' attribute requires function to be marked 'inline', attribute ignored}}
gnu_inline2() {}
// rdar://6802350
inline foo_t invalid_type() { // expected-error {{unknown type name 'foo_t'}}
}
typedef void fn_t(void);
fn_t t17;
// PR4049
unknown_type t18(void*) { // expected-error {{unknown type name 'unknown_type'}} \
// c2x-warning {{omitting the parameter name in a function definition is a C2x extension}}
}
unknown_type t19(int* P) { // expected-error {{unknown type name 'unknown_type'}}
P = P+1; // no warning.
}
// missing ',' before '...'
void t20(int i...) { } // expected-error {{requires a comma}}
int n;
void t21(int n, int (*array)[n]);
int func_e(int x) {
int func_n(int y) { // expected-error {{function definition is not allowed here}}
if (y > 22) {
return y+2;
} else {
return y-2;
}
}
return x + 3;
}
void decays(int a[3][3]); // expected-note {{passing argument to parameter 'a' here}}
void no_decay(int (*a)[3]); // expected-note {{passing argument to parameter 'a' here}}
void t22(int *ptr, int (*array)[3]) {
decays(ptr); // expected-warning {{incompatible pointer types passing 'int *' to parameter of type 'int (*)[3]'}}
no_decay(ptr); // expected-warning {{incompatible pointer types passing 'int *' to parameter of type 'int (*)[3]'}}
decays(array);
no_decay(array);
}
void const Bar (void); // ok on decl
// PR 20146
void const Bar (void) // expected-warning {{function cannot return qualified void type 'const void'}}
{
}