clang/test/SemaCXX/warn-literal-conversion.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -Wliteral-conversion -verify %s
   2
   3 void foo(int y);
   4
   5 // Warn when a literal float or double is assigned or bound to an integer.
   6 void test0() {
   7   // Float
   8   int y0 = 1.2222F; // expected-warning {{implicit conversion from 'float' to 'int' changes value from 1.2222 to 1}}
   9   int y1 = (1.2222F); // expected-warning {{implicit conversion from 'float' to 'int' changes value from 1.2222 to 1}}
  10   int y2 = (((1.2222F))); // expected-warning {{implicit conversion from 'float' to 'int' changes value from 1.2222 to 1}}
  11   int y3 = 12E-1F; // expected-warning {{implicit conversion from 'float' to 'int' changes value from 1.2 to 1}}
  12   int y4 = 1.23E1F; // expected-warning {{implicit conversion from 'float' to 'int' changes value from 12.3 to 12}}
  13   // Double
  14   int y5 = 1.2222; // expected-warning {{implicit conversion from 'double' to 'int' changes value from 1.2222 to 1}}
  15   int y6 = 12E-1; // expected-warning {{implicit conversion from 'double' to 'int' changes value from 1.2 to 1}}
  16   int y7 = 1.23E1; // expected-warning {{implicit conversion from 'double' to 'int' changes value from 12.3 to 12}}
  17   int y8 = (1.23E1); // expected-warning {{implicit conversion from 'double' to 'int' changes value from 12.3 to 12}}
  18
  19   // Test assignment to an existing variable.
  20   y8 = 2.22F; // expected-warning {{implicit conversion from 'float' to 'int' changes value from 2.22 to 2}}
  21
  22   // Test direct initialization.
  23   int y9(1.23F); // expected-warning {{implicit conversion from 'float' to 'int' changes value from 1.23 to 1}}
  24
  25   // Test passing a literal floating-point value to a function that takes an integer.
  26   foo(1.2F); // expected-warning {{implicit conversion from 'float' to 'int' changes value from 1.2 to 1}}
  27
  28   int y10 = -1.2F;  // expected-warning {{implicit conversion from 'float' to 'int' changes value from -1.2 to -1}}
  29
  30   // -Wliteral-conversion does NOT catch const values.
  31   // (-Wconversion DOES catch them.)
  32   static const float sales_tax_rate = .095F;
  33   int z = sales_tax_rate;
  34   foo(sales_tax_rate);
  35
  36   // Expressions, such as those that indicate rounding-down, should NOT produce warnings.
  37   int x = 24 * 0.5;
  38   int y = (24*60*60) * 0.25;
  39   int pennies = 123.45 * 100;
  40 }
  41
  42 // Similarly, test floating point conversion to bool. Only float values of zero
  43 // are converted to false; everything else is converted to true.
  44 void test1() {
  45   bool b1 = 0.99f; // expected-warning {{implicit conversion from 'float' to 'bool' changes value from 0.99 to true}}
  46   bool b2 = 0.99; // expected-warning {{implicit conversion from 'double' to 'bool' changes value from 0.99 to true}}
  47   // These do not warn because they can be directly converted to integral
  48   // values.
  49   bool b3 = 0.0f;
  50   bool b4 = 0.0;
  51
  52   // These all warn because they overflow the target type.
  53   short s = 32768.0; // expected-warning{{implicit conversion of out of range value from 'double' to 'short' is undefined}}
  54   unsigned short us = 65536.0; // expected-warning{{implicit conversion of out of range value from 'double' to 'unsigned short' is undefined}}
  55
  56   short s2 = -32769.0; // expected-warning{{implicit conversion of out of range value from 'double' to 'short' is undefined}}
  57   unsigned short us2 = -65537.0; // expected-warning{{implicit conversion of out of range value from 'double' to 'unsigned short' is undefined}}
  58 }
  59
  60 int a() { return 2147483647.5; } // expected-warning{{implicit conversion from 'double' to 'int' changes value from 2147483647.5 to 2147483647}}
  61 unsigned b() { return -.5; } // expected-warning{{implicit conversion from 'double' to 'unsigned int' changes value from -0.5 to 0}}
  62