fix a long-standing bug in Mu's translator

While all test pass, this change is disquieting. When I first designed
Mu I deliberately chose to exclude literal strings from most primitive
instructions both for type-checking and to avoid silently passing
through strange constructions. Nobody really needs to add a string to a
number, and am I sure no SubX instruction will cause a memory safety
issue when passed a string literal instead of a number?

But clearly I have no tests encoding this desire. And any string literal
could be replaced by an integer literal containing the exact same value,
so what are we protecting against anyway.

Let me fix the bug for now. If I run into problems I'll come back and do
this right.

0 files changed, 0 insertions, 0 deletions