`+1` constant is not allowed

[hamstergene]

Would it be a problem to allow unary plus? It is completely unimportant, but sometimes nice for readability:

    f(self._adjust(loc, -1, 0));
    f(self._adjust(loc, +1, 0)); // rust 0.3: syntax error
    f(self._adjust(loc, 0, -1));
    f(self._adjust(loc, 0, +1)); // rust 0.3: syntax error

[bblum]

Not to decisively deny this feature or anything, but I would write it with extra spaces:

    f(self._adjust(loc, -1,  0));
    f(self._adjust(loc,  1,  0));
    f(self._adjust(loc,  0, -1));
    f(self._adjust(loc,  0,  1));

[catamorphism]

We're trying not to add things, and @bblum 's suggestion seems sufficient. Sorry :-)