Proper error message for non exhaustive match #1772
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Argument to match expressions that wouldn't match any of the branches
used to have a pretty bad error message ("expecting Enum, found Enum").
This commit creates a proper variant for non-matching expressions,
pointing to the match expression and to the value the argument evaluated
to.
Currently, one position that might be lost in translation is where the
match expression was applied. It's a bit harder to track; for now, this
commit is a trivial change and is a strict improvement over the previous
situation. Let's reconsider later if this is insufficient.
vkleen
approved these changes
Jan 23, 2024
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Fixes #1771.
An argument to match expressions that wouldn't match any of the branches used to print a pretty bad error message ("expecting Enum, found Enum"). This commit creates a proper variant for non-matching expressions, and make the error reporting point to the match expression and to the value the argument evaluated to.
Currently, one position that might be lost in translation is where the match expression was applied to this argument. Here we only get the point where the match expression is defined, and what the argument evaluated to (often the application of the expression to the argument is close to the definition of the match expression, but not necessarily). The application site is a bit harder to track; for now, this PR is a trivial change and a strict improvement over the previous situation. Let's reconsider later if this proves insufficient.