Name conflicts weren't previously tested, and the diagnostics were just
a TODO, so this is also adding testing for that. But handling too.
Removing AddEntry because I think it's hard to make helpful for this
use-case when we want to do a diagnostic followup (because really,
callers want the full `.insert` result of pointer + success), and unused
otherwise.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Instructions created by splices during conversion are now evaluated, as
are instructions created in cases where we first create a placeholder
instruction and later replace it by a different instruction.
This also removes the ability to set a parse node and instruction
independently after creating an `InstId`, which could lead to them
accidentally not matching.
The parse nodes are still tracked as part of the same value store
interface in order to ensure parity, but they're split out from Inst
itself in order to reduce the size of Inst -- the expectation is that
they don't need to be passed around quite as much.
This change doesn't actually reduce the passing very much, although
there are hints of it: AddInstAndPush doesn't typically need a separate
parse node from the one on the Inst itself, for example. In a couple
spots I changed code to rely a little more on the InstId until the
ParseNode is needed, but it's very low hanging fruit where done. I think
convert could do more to not eagerly fetch the parse node before its
use, but more cleanup felt it would be easier to handle separately. I'm
currently viewing this as making such cleanup _possible_ rather than
executing on it up-front.
But also, I want to make sure there's a consensus to head in this
direction before pulling the trigger. We speculated that this would
result in the parse node being passed around less, and I do think that's
the case, although it's a bit fuzzy in the change.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Per discussion, unqualified lookup should only occur on identifiers that
existed at the time Context was initialized. As a consequence, the
resize logic in LexicalLookup may not be necessary. Even considering
metaprogramming, if metaprogramming is restricted to qualified name
lookup, it may not be necessary in the future. Support should be easy to
add if we need it. Trying to clearly document in the CHECK message what
the rationale is.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
This is primarily being done for performance reasons, removing hash
lookups. The increased memory consumption is accepted.
Refactors LexicalLookup out to its own structure.
This is currently built on top of #3575. I'm just getting to the point
where imports have enough logic that I'm thinking they may be able to
stand on their own.
Jon Ross-Perkins
