Rename Red Knot (#17820)

crates/ty_python_semantic/resources/mdtest/declaration/error.md

@@ -0,0 +1,75 @@
+# Errors while declaring
+
+## Violates previous assignment
+
+```py
+x = 1
+x: str  # error: [invalid-declaration] "Cannot declare type `str` for inferred type `Literal[1]`"
+```
+
+## Incompatible declarations
+
+```py
+def _(flag: bool):
+    if flag:
+        x: str
+    else:
+        x: int
+
+    x = 1  # error: [conflicting-declarations] "Conflicting declared types for `x`: str, int"
+```
+
+## Incompatible declarations for 2 (out of 3) types
+
+```py
+def _(flag1: bool, flag2: bool):
+    if flag1:
+        x: str
+    elif flag2:
+        x: int
+
+    # Here, the declared type for `x` is `int | str | Unknown`.
+    x = 1  # error: [conflicting-declarations] "Conflicting declared types for `x`: str, int"
+```
+
+## Incompatible declarations with bad assignment
+
+```py
+def _(flag: bool):
+    if flag:
+        x: str
+    else:
+        x: int
+
+    # error: [conflicting-declarations]
+    # error: [invalid-assignment]
+    x = b"foo"
+```
+
+## No errors
+
+Currently, we avoid raising the conflicting-declarations for the following cases:
+
+### Partial declarations
+
+```py
+def _(flag: bool):
+    if flag:
+        x: int
+
+    x = 1
+```
+
+### Partial declarations in try-except
+
+Refer to <https://github.com/astral-sh/ruff/issues/13966>
+
+```py
+def _():
+    try:
+        x: int = 1
+    except:
+        x = 2
+
+    x = 3
+```