hmpf

python · JelleZijlstra · Mar 6, 2023 · Jan 26, 2023 · Jan 26, 2023 · Jan 26, 2023
commit c1455145f31ec3272481a802d2086707dcb5e35a
diff --git a/mypy/plugins/attrs.py b/mypy/plugins/attrs.py
@@ -890,7 +890,12 @@ def evolve_callback(ctx: mypy.plugin.FunctionSigContext) -> FunctionLike:
     if len(ctx.args[0]) < 1:
         return ctx.default_signature
 
-    node = ctx.args[0][0].node
+    expr = ctx.args[0][0]
+    if not isinstance(expr, RefExpr):
+        # TODO: can't rely on expressions having a type!
+        return ctx.default_signature
+
+    node = expr.node
     if node is None:
         return ctx.default_signature
 

diff --git a/test-data/unit/check-attr.test b/test-data/unit/check-attr.test
@@ -1875,12 +1875,15 @@ import attr
 class C:
     name: str
 
+def q() -> C:
+    return C(name='foo')
+
 c = C(name='foo')
 attr.evolve()  # E: Missing positional argument "inst" in call to "evolve"
 attr.evolve(c)
 attr.evolve(c, name='bar')
 attr.evolve(
-    c,
+    q(),
     name=42,  # E: Argument "name" to "evolve" has incompatible type "int"; expected "str"
 )
 attr.evolve(