Warn about suspicious implicit conversions from floating point to bool

This warns in two specific situations:

1) For potentially swapped function arguments, e.g.

     void foo(bool, float);
     foo(1.7, false);

2) Misplaced brackets around function call arguments, e.g.

     bool InRange = fabs(a - b < delta);

   Where the last argument in a function call is implicitly converted
   from bool to float, and the function returns a float which gets
   implicitly converted to bool.

Patch by Andreas Eckleder!

llvm-svn: 162763

1 files changed, 24 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/warn-implicit-conversion-floating-point-to-bool.cpp b/clang/test/SemaCXX/warn-implicit-conversion-floating-point-to-bool.cpp
new file mode 100644
index 00000000000..1d8037aceb7
--- /dev/null
+++ b/clang/test/SemaCXX/warn-implicit-conversion-floating-point-to-bool.cpp
@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -verify -fsyntax-only %s
+
+float foof(float x);
+double food(double x);
+void foo(bool b, float f);
+
+void bar() {
+
+  float c = 1.7;
+  bool b = c;
+
+  double e = 1.7;
+  b = e;
+
+  b = foof(4.0);
+
+  b = foof(c < 1); // expected-warning {{implicit conversion turns floating-point number into bool: 'float' to 'bool'}}
+
+  b = food(e < 2); // expected-warning {{implicit conversion turns floating-point number into bool: 'double' to 'bool'}}
+
+  foo(c, b);    // expected-warning {{implicit conversion turns floating-point number into bool: 'float' to 'bool'}}
+  foo(c, c);
+
+}