bfc1650198
## Summary This is a first step toward `global` support in red-knot (#15385). I went through all the matches for `global` in the `mypy/test-data` directory, but I didn't find anything too interesting that wasn't already covered by @carljm's suggestions on Discord. I still pulled in a couple of cases for a little extra variety. I also included a section from the [PLE0118](https://docs.astral.sh/ruff/rules/load-before-global-declaration/) tests in ruff that will become syntax errors once #17463 is merged and we handle `global` statements. I don't think I figured out how to use `@Todo` properly, so please let me know if I need to fix that. I hope this is a good start to the test suite otherwise. --------- Co-authored-by: Carl Meyer <carl@astral.sh>
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3.7 KiB
global references
Implicit global in function
A name reference to a never-defined symbol in a function is implicitly a global lookup.
x = 1
def f():
reveal_type(x) # revealed: Unknown | Literal[1]
Explicit global in function
x = 1
def f():
global x
reveal_type(x) # revealed: Unknown | Literal[1]
Unassignable type in function
x: int = 1
def f():
y: int = 1
# error: [invalid-assignment] "Object of type `Literal[""]` is not assignable to `int`"
y = ""
global x
# TODO: error: [invalid-assignment] "Object of type `Literal[""]` is not assignable to `int`"
x = ""
Nested intervening scope
A global statement causes lookup to skip any bindings in intervening scopes:
x: int = 1
def outer():
x: str = ""
def inner():
global x
# TODO: revealed: int
reveal_type(x) # revealed: str
Narrowing
An assignment following a global statement should narrow the type in the local scope after the
assignment.
x: int | None
def f():
global x
x = 1
reveal_type(x) # revealed: Literal[1]
nonlocal and global
A binding cannot be both nonlocal and global. This should emit a semantic syntax error. CPython
marks the nonlocal line, while mypy, pyright, and ruff (PLE0115) mark the global line.
x = 1
def f():
x = 1
def g() -> None:
nonlocal x
global x # TODO: error: [invalid-syntax] "name 'x' is nonlocal and global"
x = None
Global declaration after global statement
def f():
global x
# TODO this should also not be an error
y = x # error: [unresolved-reference] "Name `x` used when not defined"
x = 1 # No error.
x = 2
Semantic syntax errors
Using a name prior to its global declaration in the same scope is a syntax error.
x = 1
def f():
print(x) # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x
print(x)
def f():
global x
print(x) # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x
print(x)
def f():
print(x) # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x, y
print(x)
def f():
global x, y
print(x) # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x, y
print(x)
def f():
x = 1 # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x
x = 1
def f():
global x
x = 1 # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x
x = 1
def f():
del x # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x, y
del x
def f():
global x, y
del x # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x, y
del x
def f():
del x # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x
del x
def f():
global x
del x # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x
del x
def f():
del x # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x, y
del x
def f():
global x, y
del x # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x, y
del x
def f():
print(f"{x=}") # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x
# still an error in module scope
x = None # TODO: error: [invalid-syntax] name `x` is used prior to global declaration
global x