Fix over-restrictive rule for generic cap pattern matching #2597
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The new rule for generic capability pattern matching introduced in bab5b3a turned out to be too restrictive and disallowed legitimate cases. This changes the rule from "every possible instantiation of the operand is a subtype of every possible instantiation of the pattern" to "every possible instantiation of the operand is a subtype of some possible instantiation of the pattern" Closes ponylang#2584.
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There are some issues with this that I'd like to discuss before going forward. I'll sum up my concerns in #2584. |
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I'm going to close this PR since at that point I'm fairly convinced that this isn't the correct solution. See #2584 for further discussion. |
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The new rule for generic capability pattern matching introduced in bab5b3a turned out to be too restrictive and disallowed legitimate cases.
This changes the rule from
"every possible instantiation of the operand is a subtype of every possible instantiation of the pattern"
to
"every possible instantiation of the operand is a subtype of some possible instantiation of the pattern"
Closes #2584.
No changelog entry since this fixes an unreleased bug.