From a0728cdfe1d972d2c9095cd0fa09ab51ccd7b417 Mon Sep 17 00:00:00 2001
From: vixicat <dustyisntsorusty@gmail.com>
Date: Tue, 3 Jun 2025 15:31:03 -0700
Subject: [PATCH 1/2] added tests for pep572 w/ allow-redefinition flag

---
 test-data/unit/check-pep572-redefinition.test | 72 +++++++++++++++++++
 test-data/unit/fixtures/float.pyi             |  2 +
 2 files changed, 74 insertions(+)
 create mode 100644 test-data/unit/check-pep572-redefinition.test

diff --git a/test-data/unit/check-pep572-redefinition.test b/test-data/unit/check-pep572-redefinition.test
new file mode 100644
index 000000000000..f2542be2be50
--- /dev/null
+++ b/test-data/unit/check-pep572-redefinition.test
@@ -0,0 +1,72 @@
+-- Test cases for interaction with allow-redefinition flag 
+-- and PEP572 (the walrus operator, :=)
+
+-- Base cases for no walrus operator usage & without flag
+[case testRedefine_noUsage]
+# flags: --allow-redefinition
+a: int
+a = 1
+a = 1.0 # E: Incompatible types in assignment (expression has type "float", variable has type "int")
+if (a == 1.0):
+    reveal_type(a) # N: Revealed type is "builtins.int"
+reveal_type(a) # N: Revealed type is "builtins.int"
+
+[builtins fixtures/float.pyi]
+
+[case testRedefine_withUsage]
+# flags: --allow-redefinition
+a: int
+b: int
+a = 1
+b = 2
+b = b + a
+reveal_type(a) # N: Revealed type is "builtins.int"
+a = 1.0
+if (a == 1.0):
+    reveal_type(a) # N: Revealed type is "builtins.float"
+reveal_type(a) # N: Revealed type is "builtins.float"
+
+[builtins fixtures/float.pyi]
+
+[case test_withUsage]
+# flags:
+a: int
+b: int
+a = 1
+b = 2
+b = b + a
+reveal_type(a) # N: Revealed type is "builtins.int"
+a = 1.0 # E: Incompatible types in assignment (expression has type "float", variable has type "int")
+if (a == 1.0):
+    reveal_type(a) # N: Revealed type is "builtins.int"
+reveal_type(a) # N: Revealed type is "builtins.int"
+
+[builtins fixtures/float.pyi]
+
+-- This should error due to no usage before attempted redefinition
+[case testRedefine_PEP572_noUsage]
+# flags: --allow-redefinition
+a: int
+a = 1
+
+if (a := 1.0): # E: Incompatible types in assignment (expression has type "float", variable has type "int")
+    reveal_type(a) # N: Revealed type is "builtins.int"
+reveal_type(a) # N: Revealed type is "builtins.int"
+
+[builtins fixtures/float.pyi]
+
+-- This should pass as 'a' is used before it is attempted to be redefined
+[case testRedefine_PEP572_withUsage]
+# flags: --allow-redefinition
+a: int
+b: int
+a = 1
+b = 2
+b = b + a
+reveal_type(a) # N: Revealed type is "builtins.int"
+
+if (a := 1.0):
+    reveal_type(a) # N: Revealed type is "builtins.float"
+reveal_type(a) # N: Revealed type is "builtins.float"
+
+[builtins fixtures/float.pyi]
diff --git a/test-data/unit/fixtures/float.pyi b/test-data/unit/fixtures/float.pyi
index 9e2d20f04edf..43cb29f01a83 100644
--- a/test-data/unit/fixtures/float.pyi
+++ b/test-data/unit/fixtures/float.pyi
@@ -21,6 +21,7 @@ class ellipsis: pass
 
 class int:
     def __abs__(self) -> int: ...
+    def __add__(self, other: int) -> int: ...
     def __float__(self) -> float: ...
     def __int__(self) -> int: ...
     def __mul__(self, x: int) -> int: ...
@@ -28,6 +29,7 @@ class int:
     def __rmul__(self, x: int) -> int: ...
 
 class float:
+    def __eq__(self, other: float) -> bool: ...
     def __float__(self) -> float: ...
     def __int__(self) -> int: ...
     def __mul__(self, x: float) -> float: ...

From 07c1edb0f981e1f199ea649c061226234f390885 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Tue, 3 Jun 2025 23:26:03 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 test-data/unit/check-pep572-redefinition.test | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test-data/unit/check-pep572-redefinition.test b/test-data/unit/check-pep572-redefinition.test
index f2542be2be50..78655f43dc93 100644
--- a/test-data/unit/check-pep572-redefinition.test
+++ b/test-data/unit/check-pep572-redefinition.test
@@ -1,4 +1,4 @@
--- Test cases for interaction with allow-redefinition flag 
+-- Test cases for interaction with allow-redefinition flag
 -- and PEP572 (the walrus operator, :=)
 
 -- Base cases for no walrus operator usage & without flag