[Issue 18248] New: radix overload of std.conv.parse fails to throw on non-empty range without number

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18248

          Issue ID: 18248
           Summary: radix overload of std.conv.parse fails to throw on
                    non-empty range without number
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: phobos
          Assignee: nobody at puremagic.com
          Reporter: issues.dlang at jmdavisProg.com

Per the documentation for std.conv.parse, parse is supposed to throw if "no
character of the input was meaningfully converted." The main overload of parse
does this, and the radix overload does if it's given a radix of 10 (since that
just calls the main overload) or if the range is empty. However, if you pass it
a radix other than 10 and string that is not empty but which does not start
with a number, it returns 0 on failure instead of throwing. e.g. this code 
should throw

----------------
void main()
{
    import std.conv;
    auto str = ";";
    assert(str.parse!uint(16) == 0); // should throw
    assert(str == ";");

}
----------------

However, it passes.

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