New semantic analyzer: refactor analysis of assignments #6412
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Changing mypy's internals
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Mar 15, 2019
…rward (#6527) Fixes #6412 Fixes #6453 In this PR: * Wait until we can classify r.h.s. of an assignment as normal, type alias, named tuple etc. * Choose the corresponding branch instead of performing all of them (as it used to be before) * Never create (or rely on creation of) temporary `Var`s * Add every symbol to symbol table only once (as it is done for classes) * Don't "patch" existing symbols (with one exception for type variables, see below) * Add and update docstrings and comments Notes: * I allow placeholders for type alias targets and NewTypes targets, they essentially behave as base classes. In general I make logic for type aliases and NewTypes much more similar to logic of class definitions (especially NewTypes), this allows to support a whole bunch of tricky forward references * I don't store types with placeholders in annotations, and instead if an alias target got updated (e.g. placeholders are resolved), I set `progress=True` Follow-ups: * There is still a small hack to keep compatibility with old analyzer in type checker, but now it is basically "don't use binder for l.h.s. of special forms" * Type variable declarations still have a bug that duplicate type variable definition is not reported as error, second one silently wins, this will be fixed in a separate PR * This PR doesn't aim to fix aspects of assignment analysis related to #6422, that will be also a separate PR Test updates: * Add and enable more tests for type aliases and NewTypes * Add test for cyclic definition error messages * Change order of error messages on the same line in few tests * Enable one test file where previously only some tests were opted in (I think it was not enabled by mistake in one of the previous PRs, I enable it here since order of errors in one test in that file is affected by this PR.)
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This is a follow-up for #6390
Assignment statements can create a bunch of different symbol nodes:
Because of this current implementation is messy and has some hacks. We should refactor this to happen in two steps:
The tricky corner case is enums:
c = Color['Red']looks like a type alias, but this should create a variable.The text was updated successfully, but these errors were encountered: