• via Digitalmars-d-bugs (51/51) Dec 22 2015 https://issues.dlang.org/show_bug.cgi?id=15467

via Digitalmars-d-bugs <digitalmars-d-bugs puremagic.com> writes:

https://issues.dlang.org/show_bug.cgi?id=15467

          Issue ID: 15467
           Summary: Compiler incorrectly flags a function as throwing an
                    exception though it is caught
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: samjnaa gmail.com

In relation to https://github.com/D-Programming-Language/phobos/pull/3751 I
created the following code:

mixin template basicExceptionCtors()
{
    this(string msg, string file = __FILE__, size_t line = __LINE__, Throwable
next = null)  safe pure nothrow
    {
        super(msg, file, line, next);
    }
    this(string msg, Throwable next, string file = __FILE__, size_t line =
__LINE__)  safe pure nothrow
    {
        super(msg, file, line, next);
    }
}
pure nothrow  safe unittest
{
    class MeaCulpa: Exception
    {
        mixin basicExceptionCtors;
    }
    try
        throw new MeaCulpa("test");
    catch (MeaCulpa e)
    {
        assert(e.msg == "test");
        assert(e.file == __FILE__);
        assert(e.line == __LINE__ - 5);
    }
}
void main(){}

Compiling the above I get the error:

<src>(19): Error: <src>.__unittestL12_1.MeaCulpa is thrown but not caught
<src>(12): Error: function '<src>.__unittestL12_1' is nothrow yet may throw

Clearly the thrown exception is caught. As such the compiler incorrectly flags
this as a violation of the `nothrow` declaration and should be fixed.

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