Hygiene for methods #15537
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Hygiene for methods #15537
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should prevent future bugs
The let-syntax expander is different in that it doesn't apply a mark to its token trees before expansion. This is used for macro_rules, and it's because macro_rules is essentially MTWT's let-syntax. You don't want to mark before expand sees let-syntax, because there's no "after" syntax to mark again. In some sense, the cleaner approach might be to introduce a new AST node that macro_rules expands into; this would make it clearer that the expansion of a macro is distinct from the addition of a new macro binding. This should work for now, though...
I believe this comment is now irrelevant, as a result of commit 6757053
formerly, the self identifier was being discarded during parsing, which stymies hygiene. The best fix here seems to be to attach a self identifier to ExplicitSelf_, a change that rippled through the rest of the compiler, but without any obvious damage.
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This patch adds hygiene for methods. This one was more difficult than the others, due principally to issues surrounding `self`. Specifically, there were a whole bunch of places in the code that assumed that a `self` identifier could be discarded and then made up again later, causing the discard of contexts and hygiene breakage.
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This patch adds hygiene for methods. This one was more difficult than the others, due principally to issues surrounding
self. Specifically, there were a whole bunch of places in the code that assumed that aselfidentifier could be discarded and then made up again later, causing the discard of contexts and hygiene breakage.