MAINT: Import `mypy` via a try/except approach

Fixes an issue where the `pypy` tests would fail

1 files changed, 23 insertions, 15 deletions

diff --git a/numpy/typing/mypy_plugin.py b/numpy/typing/mypy_plugin.py
index 341870167..505a01a0b 100644
--- a/numpy/typing/mypy_plugin.py
+++ b/numpy/typing/mypy_plugin.py
@@ -4,14 +4,17 @@ import typing as t
 
 import numpy as np
 
-import mypy.types
-from mypy.types import Type
-from mypy.plugin import Plugin, AnalyzeTypeContext
+try:
+    import mypy.types
+    from mypy.types import Type
+    from mypy.plugin import Plugin, AnalyzeTypeContext
+    _HookFunc = t.Callable[[AnalyzeTypeContext], Type]
+    MYPY_EX: t.Optional[ModuleNotFoundError] = None
+except ModuleNotFoundError as ex:
+    MYPY_EX = ex
 
 __all__: t.List[str] = []
 
-HookFunc = t.Callable[[AnalyzeTypeContext], Type]
-
 
 def _get_precision_dict() -> t.Dict[str, str]:
     names = [
@@ -39,7 +42,7 @@ def _get_precision_dict() -> t.Dict[str, str]:
 _PRECISION_DICT = _get_precision_dict()
 
 
-def _hook(ctx: AnalyzeTypeContext) -> Type:
+def _hook(ctx: "AnalyzeTypeContext") -> "Type":
     """Replace a type-alias with a concrete ``NBitBase`` subclass."""
     typ, _, api = ctx
     name = typ.name.split(".")[-1]
@@ -47,15 +50,20 @@ def _hook(ctx: AnalyzeTypeContext) -> Type:
     return api.named_type(name_new)
 
 
-class _NumpyPlugin(Plugin):
-    """A plugin for assigning platform-specific `numpy.number` precisions."""
+if MYPY_EX is None:
+    class _NumpyPlugin(Plugin):
+        """A plugin for assigning platform-specific `numpy.number` precisions."""
 
-    def get_type_analyze_hook(self, fullname: str) -> t.Optional[HookFunc]:
-        if fullname in _PRECISION_DICT:
-            return _hook
-        return None
+        def get_type_analyze_hook(self, fullname: str) -> t.Optional[_HookFunc]:
+            if fullname in _PRECISION_DICT:
+                return _hook
+            return None
 
+    def plugin(version: str) -> t.Type[_NumpyPlugin]:
+        """An entry-point for mypy."""
+        return _NumpyPlugin
 
-def plugin(version: str) -> t.Type[_NumpyPlugin]:
-    """An entry-point for mypy."""
-    return _NumpyPlugin
+else:
+    def plugin(version: str) -> t.Type["_NumpyPlugin"]:
+        """An entry-point for mypy."""
+        raise MYPY_EX