Canonicalize all nested goals together at once when making response #124689
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Since we canonicalize each added goal separately, any time we add two goals that should be linked by an inference variable local to our evaluation, they end up unlinked in the nested goals of a inspect candidate. For example,
when proving
(): Foo
, we expect two nested goals:<() as Constrain>::Output = ?0
and?0: Bar
. However, we end up actually instantiating the second goal as?1: Bar
, leaving it totally unconstrained. This leads to anomalous states, such as a candidate withCertainty::Yes
but withCertainty::Maybe
in its nested goals❗This PR aims to fix this problem by canonicalizing all of the nested goals all together at once, which means that we'll canonicalize any duplicated instances of a variable as a single variable.
r? lcnr