feat: str.join constant folding support (and bytes.join for mypyc) #19884
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| elif isinstance(expr, CallExpr) and isinstance(callee := expr.callee, MemberExpr): | ||
| folded_callee = constant_fold_expr(builder, callee.expr) | ||
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| # builtins.str methods |
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We can constant fold quite a lot of cases for builtins without too much code. I have an idea for how to implement this cleanly but that's outside the scope of this PR.
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I don't see any reason for this test to not fail based on the code changes. I think I might be using TupleType incorrectly here, or accessing the type in a less-than-optimal way. Any advice here would be appreciated. |
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Diff from mypy_primer, showing the effect of this PR on open source code: graphql-core (https://github.com/graphql-python/graphql-core)
- version: 1.19.0+dev.19697af9051707b4db55bc2d5301436d872f452c
+ version: 1.19.0+dev.9ea11f958df51f70158064260d71ac32dfedf771
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Intent:
Mypyc can currently handle constant folding of f-strings, but mypy itself cannot.
Changes:
str.joinexpressions. It is a critical first step for implementing f-string support, which will come in a follow-up PR.I can break those changes up if you'd prefer.