generate symchoice for ambiguous types in templates & generics + handle types in symchoices #23997
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Araq
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Aug 21, 2024
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Thanks for your hard work on this PR! Hint: mm: orc; opt: speed; options: -d:release |
narimiran
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…le types in symchoices (#23997) fixes #23898, supersedes #23966 and #23990 Since #20631 ambiguous type symbols in templates are rejected outright, now we generate a symchoice for type nodes if they're ambiguous, a generalization of what was done in #22375. This is done for generics as well. Symchoices also handle type symbols better now, ensuring their type is a `typedesc` type; this probably isn't necessary for everything to work but it makes the logic more robust. Similar to #23989, we have to prepare for the fact that ambiguous type symbols behave differently than normal type symbols and either error normally or relegate to other routine symbols if the symbol is being called. Generating a symchoice emulates this behavior, `semExpr` will find the type symbol first, but since the symchoice has other symbols, it will count as an ambiguous type symbol. I know it seems spammy to carry around an ambiguity flag everywhere, but in the future when we have something like #23104 we could just always generate a symchoice, and the symchoice itself would carry the info of whether the first symbol was ambiguous. But this could harm compiler performance/memory use, it might be better to generate it only when we have to, which in the case of type symbols is only when they're ambiguous. (cherry picked from commit 09dcff7)
metagn
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Araq
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…24180) fixes #19866 given #23997 When searching for a module-qualified symbol, `qualifiedLookUp` tries to obtain the raw identifier from the RHS of the dot field. However it only does this when the RHS is either an `nkIdent` or an `nkAccQuoted` node, not when the node is a resolved symbol or a symchoice, such as in templates and generics when the module symbol can't be resolved yet. Since the LHS is a module symbol when the compiler checks for this, any resolved symbol information doesn't matter, since it has to be a member of the module. So we now obtain the identifier from these nodes as well as the unresolved identifier nodes. The test is a bit niche and possibly not officially supported, but this is likely a more general problem and I just couldn't think of another test that would be more "proper". It's better than the error message `'a' has no type` at least.
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fixes #23898, supersedes #23966 and #23990
Since #20631 ambiguous type symbols in templates are rejected outright, now we generate a symchoice for type nodes if they're ambiguous, a generalization of what was done in #22375. This is done for generics as well. Symchoices also handle type symbols better now, ensuring their type is a
typedesctype; this probably isn't necessary for everything to work but it makes the logic more robust.Similar to #23989, we have to prepare for the fact that ambiguous type symbols behave differently than normal type symbols and either error normally or relegate to other routine symbols if the symbol is being called. Generating a symchoice emulates this behavior,
semExprwill find the type symbol first, but since the symchoice has other symbols, it will count as an ambiguous type symbol.I know it seems spammy to carry around an ambiguity flag everywhere, but in the future when we have something like #23104 we could just always generate a symchoice, and the symchoice itself would carry the info of whether the first symbol was ambiguous. But this could harm compiler performance/memory use, it might be better to generate it only when we have to, which in the case of type symbols is only when they're ambiguous.