Bug 2568 – Warning Inside Template Causes Instantiation Error

----------------- void foo(T)(T arg) { int i = 999; byte b = i; } void main() { float f; foo(f); } ----------------- The above code compiles correctly with warnings disabled. But when warnings are enabled, an template instantiation error is generated: ----------------- warning - main.d(4): Error: implicit conversion of expression (i) of type int to byte can cause loss of data main.d(10): template instance main_.foo!(float) error instantiating ----------------- This might be related to #2567 and DMD's general treatment of warnings as errors.

In dmd 1.063 this no longer generates the error, but does cause the warning. The failed compilation is in line with dmd's treatment of errors. The -wi switch has since been introduced for the case you do not want to treat warnings as error.