clang/test/Parser/extra-semi-resulting-in-nullstmt.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -Wextra-semi-stmt -verify %s
   2 // RUN: cp %s %t
   3 // RUN: %clang_cc1 -x c++ -Wextra-semi-stmt -fixit %t
   4 // RUN: %clang_cc1 -x c++ -Wextra-semi-stmt -Werror %t
   5
   6 #define GOODMACRO(varname) int varname
   7 #define BETTERMACRO(varname) GOODMACRO(varname);
   8 #define NULLMACRO(varname)
   9
  10 enum MyEnum {
  11   E1,
  12   E2
  13 };
  14
  15 void test() {
  16   ; // expected-warning {{empty expression statement has no effect; remove unnecessary ';' to silence this warning}}
  17   ;
  18
  19   // This removal of extra semi also consumes all the comments.
  20   // clang-format off
  21   ;;;
  22   // clang-format on
  23
  24   // clang-format off
  25   ;NULLMACRO(ZZ);
  26   // clang-format on
  27
  28   {}; // expected-warning {{empty expression statement has no effect; remove unnecessary ';' to silence this warning}}
  29
  30   {
  31     ; // expected-warning {{empty expression statement has no effect; remove unnecessary ';' to silence this warning}}
  32   }
  33
  34   if (true) {
  35     ; // expected-warning {{empty expression statement has no effect; remove unnecessary ';' to silence this warning}}
  36   }
  37
  38   GOODMACRO(v0); // OK
  39
  40   GOODMACRO(v1;) // OK
  41
  42   BETTERMACRO(v2) // OK
  43
  44   BETTERMACRO(v3;) // Extra ';', but within macro expansion, so ignored.
  45
  46   BETTERMACRO(v4); // expected-warning {{empty expression statement has no effect; remove unnecessary ';' to silence this warning}}
  47
  48   BETTERMACRO(v5;); // expected-warning {{empty expression statement has no effect; remove unnecessary ';' to silence this warning}}
  49
  50   NULLMACRO(v6) // OK
  51
  52   NULLMACRO(v7); // OK. This could be either GOODMACRO() or BETTERMACRO() situation, so we can't know we can drop it.
  53
  54   if (true)
  55     ; // OK
  56
  57   while (true)
  58     ; // OK
  59
  60   do
  61     ; // OK
  62   while (true);
  63
  64   for (;;) // OK
  65     ;      // OK
  66
  67   MyEnum my_enum;
  68   switch (my_enum) {
  69   case E1:
  70     // stuff
  71     break;
  72   case E2:; // OK
  73   }
  74
  75   for (;;) {
  76     for (;;) {
  77       goto contin_outer;
  78     }
  79   contin_outer:; // OK
  80   }
  81 }
  82
  83 ;
  84
  85 namespace NS {};
  86
  87 void foo(int x) {
  88   switch (x) {
  89   case 0:
  90     [[fallthrough]];
  91   case 1:
  92     return;
  93   }
  94 }
  95
  96 [[]];