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[1.12 regression] New error on type[memoryView] | type[str] #17942

@Christian-B

Description

@Christian-B

Bug Report

new to 1.12.0
incorrect error message on union of two type one being memoryview

Complete file checked:

"""
a_type: type[memoryview] | type[str] = memoryview
"""

mypy 1.11.2 no error

mypy 1.12.0
Incompatible default for argument "a_type" (default has type "type[memoryview[Any]]", argument has type "type[memoryview[int]] | type[str]")

Your Environment
github action ubuntu various , python various

  • Mypy command-line flags:
    -no flags
  • Mypy configuration options from mypy.ini (and other config files):
  • None
  • Python version used: via github actions
    3.8, 3.9, 3.10, 3.11, 3.12 and 3.13

while
"""
a_type: type[memoryview] = memoryview
""""
Works ok!

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bugmypy got something wrongtopic-pep-696TypeVar defaults

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