Fix type query for recursive aliases (#14136)

See #14130 for context. Btw it looks like these `Any` reports are quite broken in general. Some issues I found: * Many types are reported twice (even non-recursive) * Explicit `Any` in alias r.h.s are not counted (because of reckless `res = make_any_non_explicit(res)` in semanal.py) * For generic aliases we count their r.h.s. as containing `Any` from omitted generics I tried to fix these things, but it is not trivial, so maybe we can do it later in a separate PR.
python · Nov 19, 2022 · 6cd8e00 · 6cd8e00
1 parent a2477ff
commit 6cd8e00
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Showing 3 changed files with 32 additions and 18 deletions.
diff --git a/mypy/type_visitor.py b/mypy/type_visitor.py
@@ -404,24 +404,16 @@ def visit_placeholder_type(self, t: PlaceholderType) -> T:
  return self.query_types(t.args)
 
  def visit_type_alias_type(self, t: TypeAliasType) -> T:
+ # Skip type aliases already visited types to avoid infinite recursion.
+ # TODO: Ideally we should fire subvisitors here (or use caching) if we care
+ # about duplicates.
+ if t in self.seen_aliases:
+ return self.strategy([])
+ self.seen_aliases.add(t)
  if self.skip_alias_target:
  return self.query_types(t.args)
  return get_proper_type(t).accept(self)
 
  def query_types(self, types: Iterable[Type]) -> T:
- """Perform a query for a list of types.
-
- Use the strategy to combine the results.
- Skip type aliases already visited types to avoid infinite recursion.
- """
- res: list[T] = []
- for t in types:
- if isinstance(t, TypeAliasType):
- # Avoid infinite recursion for recursive type aliases.
- # TODO: Ideally we should fire subvisitors here (or use caching) if we care
- # about duplicates.
- if t in self.seen_aliases:
- continue
- self.seen_aliases.add(t)
- res.append(t.accept(self))
- return self.strategy(res)
+ """Perform a query for a list of types using the strategy to combine the results."""
+ return self.strategy([t.accept(self) for t in types])
diff --git a/mypy/typeanal.py b/mypy/typeanal.py
@@ -450,7 +450,7 @@ def try_analyze_special_unbound_type(self, t: UnboundType, fullname: str) -> Typ
  if fullname == "builtins.None":
  return NoneType()
  elif fullname == "typing.Any" or fullname == "builtins.Any":
- return AnyType(TypeOfAny.explicit)
+ return AnyType(TypeOfAny.explicit, line=t.line, column=t.column)
  elif fullname in FINAL_TYPE_NAMES:
  self.fail(
  "Final can be only used as an outermost qualifier in a variable annotation",

diff --git a/test-data/unit/reports.test b/test-data/unit/reports.test
@@ -103,6 +103,28 @@ class A(object):
 </body>
 </html>
 
+[case testNoCrashRecursiveAliasInReport]
+# cmd: mypy --any-exprs-report report n.py
+
+[file n.py]
+from typing import Union, List, Any, TypeVar
+
+Nested = List[Union[Any, Nested]]
+T = TypeVar("T")
+NestedGen = List[Union[T, NestedGen[T]]]
+
+x: Nested
+y: NestedGen[int]
+z: NestedGen[Any]
+
+[file report/any-exprs.txt]
+[outfile report/types-of-anys.txt]
+ Name Unannotated Explicit Unimported Omitted Generics Error Special Form Implementation Artifact
+-----------------------------------------------------------------------------------------------------------------
+ n 0 4 0 8 0 0 0
+-----------------------------------------------------------------------------------------------------------------
+Total 0 4 0 8 0 0 0
+
 [case testTypeVarTreatedAsEmptyLine]
 # cmd: mypy --html-report report n.py
 
@@ -480,7 +502,7 @@ namespace_packages = True
 <link rel="stylesheet" type="text/css" href="../../../mypy-html.css">
 </head>
 <body>
-<h2>folder.subfolder.something</h2> 
+<h2>folder.subfolder.something</h2>
 <table>
 <caption>folder/subfolder/something.py</caption>
 <tbody><tr>