Add check Y091 for raise in function bodies

README.rst

@@ -81,6 +81,7 @@ The following warnings are disabled by default:
          x: str
          def __init__(self, x: str) -> None: ...
 
+* Y091: Function body must not contain "raise".
 
 License
 -------

pyi.py

@@ -299,8 +299,9 @@ def visit_FunctionDef(self, node: ast.FunctionDef) -> None:
                     statement.value, ast.Ellipsis
                 ):
                     continue
-            # allow "raise", a number of stubs have this
+            # special-case raise for backwards compatibility
             if isinstance(statement, ast.Raise):
+                self.error(statement, Y091)
                 continue
             # allow assignments in constructor for now
             # (though these should probably be changed)
@@ -418,5 +419,6 @@ def should_warn(self, code):
 Y013 = 'Y013 Non-empty class body must not contain "..."'
 Y014 = 'Y014 Default values for arguments must be "..."'
 Y090 = "Y090 Use explicit attributes instead of assignments in __init__"
+Y091 = 'Y091 Function body must not contain "raise"'
 
-DISABLED_BY_DEFAULT = [Y090]
+DISABLED_BY_DEFAULT = [Y090, Y091]

tests/raise.pyi

@@ -0,0 +1,6 @@
+class Foo:
+    def __init__(self) -> None:
+        raise ValueError()  # Y091
+
+    def foo(self) -> None:
+        raise ValueError()  # Y091

tests/test_pyi.py

@@ -191,6 +191,16 @@ def test_empty_init(self) -> None:
             "emptyinit.pyi", stdout_lines=stdout_lines, extra_options=("--select=Y090",)
         )
 
+    def test_raise_in_function_body(self) -> None:
+        self.checkFileOutput("raise.pyi", stdout_lines=())
+        stdout_lines = (
+            '3:9: Y091 Function body must not contain "raise"',
+            '6:9: Y091 Function body must not contain "raise"',
+        )
+        self.checkFileOutput(
+            "raise.pyi", stdout_lines=stdout_lines, extra_options=("--select=Y091",)
+        )
+
     def test_defaults(self) -> None:
         stdout_lines = (
             '3:17: Y011 Default values for typed arguments must be "..."',