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@BobTheBuidler BobTheBuidler commented Sep 17, 2025

It should be possible to "constant fold" a LOC such as:

requests.get(some_url, headers={"k0": "v0", "k1": "v1"})

We can't simply create a dictionary constant since dicts are mutable and we don't know what's going to happen in the called function, but we can hold a template dict in memory and PyDict_Copy it when it's time for use. This skips the hashing and any resizing during construction, and simply takes the hash table from the existing dict instead, which will be (possibly much) quicker than constructing from scratch each time.

This PR does that.


# Supported Python literal types. All tuple / frozenset items must have supported
# Supported Python literal types. All tuple / frozenset / dict items must have supported
# literal types as well, but we can't represent the type precisely.
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is there a reason we can't represent the type precisely? I think with a HashableLiteralValue defined before LiteralValue, we can do it pretty cleanly

@BobTheBuidler BobTheBuidler changed the title [mypyc] feat: constant folding for DictExpr [mypyc] feat: constant folding for DictExpr [1/1] Oct 1, 2025
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