From 196b2a32be9080b025146d3029fb95a2e579492f Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 15 May 2024 16:44:17 +0100
Subject: [PATCH] Fix crash on undefined name in generic method

---
 mypy/semanal.py                     | 12 +++++++++---
 test-data/unit/check-python312.test | 10 ++++++++++
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index a63e58ba54f2..f92471c159de 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -1653,7 +1653,7 @@ def push_type_args(
             tvs.append((p.name, tv))
 
         for name, tv in tvs:
-            self.add_symbol(name, tv, context)
+            self.add_symbol(name, tv, context, no_progress=True)
 
         return tvs
 
@@ -5967,6 +5967,7 @@ def lookup(
         for table in reversed(self.locals):
             if table is not None and name in table:
                 return table[name]
+
         # 4. Current file global scope
         if name in self.globals:
             return self.globals[name]
@@ -6279,6 +6280,7 @@ def add_symbol(
         module_hidden: bool = False,
         can_defer: bool = True,
         escape_comprehensions: bool = False,
+        no_progress: bool = False,
     ) -> bool:
         """Add symbol to the currently active symbol table.
 
@@ -6300,7 +6302,9 @@ def add_symbol(
         symbol = SymbolTableNode(
             kind, node, module_public=module_public, module_hidden=module_hidden
         )
-        return self.add_symbol_table_node(name, symbol, context, can_defer, escape_comprehensions)
+        return self.add_symbol_table_node(
+            name, symbol, context, can_defer, escape_comprehensions, no_progress
+        )
 
     def add_symbol_skip_local(self, name: str, node: SymbolNode) -> None:
         """Same as above, but skipping the local namespace.
@@ -6331,6 +6335,7 @@ def add_symbol_table_node(
         context: Context | None = None,
         can_defer: bool = True,
         escape_comprehensions: bool = False,
+        no_progress: bool = False,
     ) -> bool:
         """Add symbol table node to the currently active symbol table.
 
@@ -6379,7 +6384,8 @@ def add_symbol_table_node(
                     self.name_already_defined(name, context, existing)
         elif name not in self.missing_names[-1] and "*" not in self.missing_names[-1]:
             names[name] = symbol
-            self.progress = True
+            if not no_progress:
+                self.progress = True
             return True
         return False
 
diff --git a/test-data/unit/check-python312.test b/test-data/unit/check-python312.test
index 2b85020e6609..53656ae5e3fb 100644
--- a/test-data/unit/check-python312.test
+++ b/test-data/unit/check-python312.test
@@ -948,3 +948,13 @@ type B[T] = Foo[T]
 [out2]
 tmp/a.py:3: note: Revealed type is "builtins.str"
 tmp/a.py:5: note: Revealed type is "b.Foo[builtins.int]"
+
+[case testPEP695UndefinedNameInGenericFunction]
+# mypy: enable-incomplete-feature=NewGenericSyntax
+
+def f[T](x: T) -> T:
+    return unknown()  # E: Name "unknown" is not defined
+
+class C:
+    def m[T](self, x: T) -> T:
+        return unknown()  # E: Name "unknown" is not defined