Bump missing return statement note to error severity

Author: ddfisher

mypy/checker.py

@@ -654,7 +654,7 @@ def is_implicit_any(t: Type) -> bool:
                     if self.is_trivial_body(defn.body):
                         pass
                     else:
-                        self.msg.note(messages.MISSING_RETURN_STATEMENT, defn)
+                        self.msg.fail(messages.MISSING_RETURN_STATEMENT, defn)
 
             self.return_types.pop()
 

test-data/unit/check-async-await.test

@@ -20,7 +20,7 @@ async def f() -> int:
     make_this_not_trivial = 1
 [builtins fixtures/async_await.pyi]
 [out]
-main:2: note: Missing return statement
+main:2: error: Missing return statement
 
 [case testAsyncDefReturnWithoutValue]
 # flags: --fast-parser

test-data/unit/check-optional.test

@@ -493,7 +493,7 @@ def f() -> None:
 def g() -> int:
   1 + 1  #
 [out]
-main:5: note: Missing return statement
+main:5: error: Missing return statement
 
 [case testGenericTypeAliasesOptional]
 from typing import TypeVar, Generic, Optional

test-data/unit/check-statements.test

@@ -63,7 +63,7 @@ def f() -> Generator[int, None, str]:
 
 [case testNoReturnInGenerator]
 from typing import Generator
-def f() -> Generator[int, None, str]:  # N: Missing return statement
+def f() -> Generator[int, None, str]:  # E: Missing return statement
     yield 1
 [out]
 

test-data/unit/check-warnings.test

@@ -71,7 +71,7 @@ def g() -> int:
         return 1
 [builtins fixtures/list.pyi]
 [out]
-main:5: note: Missing return statement
+main:5: error: Missing return statement
 
 [case testNoReturnWhile]
 # flags: --warn-no-return
@@ -95,7 +95,7 @@ def j() -> int:
             continue
 [builtins fixtures/list.pyi]
 [out]
-main:7: note: Missing return statement
+main:7: error: Missing return statement
 
 [case testNoReturnExcept]
 # flags: --warn-no-return
@@ -122,7 +122,7 @@ def h() -> int:
         return 1
 [builtins fixtures/exception.pyi]
 [out]
-main:2: note: Missing return statement
+main:2: error: Missing return statement
 
 [case testNoReturnEmptyBodyWithDocstring]
 def f() -> int: