Rename Red Knot (#17820)

crates/ty_python_semantic/resources/mdtest/conditional/if_statement.md

@@ -0,0 +1,163 @@
+# If statements
+
+## Simple if
+
+```py
+def _(flag: bool):
+    y = 1
+    y = 2
+
+    if flag:
+        y = 3
+
+    reveal_type(y)  # revealed: Literal[2, 3]
+```
+
+## Simple if-elif-else
+
+```py
+def _(flag: bool, flag2: bool):
+    y = 1
+    y = 2
+
+    if flag:
+        y = 3
+    elif flag2:
+        y = 4
+    else:
+        r = y
+        y = 5
+        s = y
+    x = y
+
+    reveal_type(x)  # revealed: Literal[3, 4, 5]
+
+    # revealed: Literal[2]
+    # error: [possibly-unresolved-reference]
+    reveal_type(r)
+
+    # revealed: Literal[5]
+    # error: [possibly-unresolved-reference]
+    reveal_type(s)
+```
+
+## Single symbol across if-elif-else
+
+```py
+def _(flag: bool, flag2: bool):
+    if flag:
+        y = 1
+    elif flag2:
+        y = 2
+    else:
+        y = 3
+
+    reveal_type(y)  # revealed: Literal[1, 2, 3]
+```
+
+## if-elif-else without else assignment
+
+```py
+def _(flag: bool, flag2: bool):
+    y = 0
+
+    if flag:
+        y = 1
+    elif flag2:
+        y = 2
+    else:
+        pass
+
+    reveal_type(y)  # revealed: Literal[0, 1, 2]
+```
+
+## if-elif-else with intervening assignment
+
+```py
+def _(flag: bool, flag2: bool):
+    y = 0
+
+    if flag:
+        y = 1
+        z = 3
+    elif flag2:
+        y = 2
+    else:
+        pass
+
+    reveal_type(y)  # revealed: Literal[0, 1, 2]
+```
+
+## Nested if statement
+
+```py
+def _(flag: bool, flag2: bool):
+    y = 0
+
+    if flag:
+        if flag2:
+            y = 1
+
+    reveal_type(y)  # revealed: Literal[0, 1]
+```
+
+## if-elif without else
+
+```py
+def _(flag: bool, flag2: bool):
+    y = 1
+    y = 2
+
+    if flag:
+        y = 3
+    elif flag2:
+        y = 4
+
+    reveal_type(y)  # revealed: Literal[2, 3, 4]
+```
+
+## if-elif with assignment expressions in tests
+
+```py
+def check(x: int) -> bool:
+    return bool(x)
+
+if check(x := 1):
+    x = 2
+elif check(x := 3):
+    x = 4
+
+reveal_type(x)  # revealed: Literal[2, 3, 4]
+```
+
+## constraints apply to later test expressions
+
+```py
+def check(x) -> bool:
+    return bool(x)
+
+def _(flag: bool):
+    x = 1 if flag else None
+    y = 0
+
+    if x is None:
+        pass
+    elif check(y := x):
+        pass
+
+    reveal_type(y)  # revealed: Literal[0, 1]
+```
+
+## Condition with object that implements `__bool__` incorrectly
+
+```py
+class NotBoolable:
+    __bool__: int = 3
+
+# error: [unsupported-bool-conversion] "Boolean conversion is unsupported for type `NotBoolable`"
+if NotBoolable():
+    ...
+# error: [unsupported-bool-conversion] "Boolean conversion is unsupported for type `NotBoolable`"
+elif NotBoolable():
+    ...
+```