Turn all warnings and bare notes into errors (#6650)

This means that all diagnostics are errors, which maybe have some
notes "attached" to them.
This makes sense, since all diagnostics cause an error exit code.

Fixes #6574.

Author: msullivan

mypy/build.py

@@ -2180,7 +2180,7 @@ def generate_unused_ignore_notes(self) -> None:
             # those errors to avoid spuriously flagging them as unused ignores.
             if self.meta:
                 self.verify_dependencies(suppressed_only=True)
-            self.manager.errors.generate_unused_ignore_notes(self.xpath)
+            self.manager.errors.generate_unused_ignore_errors(self.xpath)
 
 
 # Module import and diagnostic glue
@@ -2376,7 +2376,7 @@ def skipping_module(manager: BuildManager, line: int, caller_state: Optional[Sta
     manager.errors.set_file(caller_state.xpath, caller_state.id)
     manager.errors.report(line, 0,
                           "Import of '%s' ignored" % (id,),
-                          severity='note')
+                          severity='error')
     manager.errors.report(line, 0,
                           "(Using --follow-imports=error, module not passed on command line)",
                           severity='note', only_once=True)
@@ -2392,7 +2392,7 @@ def skipping_ancestor(manager: BuildManager, id: str, path: str, ancestor_for: '
     manager.errors.set_import_context([])
     manager.errors.set_file(ancestor_for.xpath, ancestor_for.id)
     manager.errors.report(-1, -1, "Ancestor package '%s' ignored" % (id,),
-                          severity='note', only_once=True)
+                          severity='error', only_once=True)
     manager.errors.report(-1, -1,
                           "(Using --follow-imports=error, submodule passed on command line)",
                           severity='note', only_once=True)

mypy/checker.py

@@ -951,7 +951,7 @@ def check_func_def(self, defn: FuncItem, typ: CallableType, name: Optional[str])
                     # entirely pass/Ellipsis.
                     if isinstance(return_type, UninhabitedType):
                         # This is a NoReturn function
-                        self.msg.note(message_registry.INVALID_IMPLICIT_RETURN, defn)
+                        self.msg.fail(message_registry.INVALID_IMPLICIT_RETURN, defn)
                     else:
                         self.msg.fail(message_registry.MISSING_RETURN_STATEMENT, defn)
 
@@ -2793,7 +2793,7 @@ def visit_assert_stmt(self, s: AssertStmt) -> None:
             self.expr_checker.accept(s.msg)
 
         if isinstance(s.expr, TupleExpr) and len(s.expr.items) > 0:
-            self.warn(message_registry.MALFORMED_ASSERT, s)
+            self.fail(message_registry.MALFORMED_ASSERT, s)
 
         # If this is asserting some isinstance check, bind that type in the following code
         true_map, _ = self.find_isinstance_check(s.expr)
@@ -3747,10 +3747,6 @@ def fail(self, msg: str, context: Context) -> None:
         """Produce an error message."""
         self.msg.fail(msg, context)
 
-    def warn(self, msg: str, context: Context) -> None:
-        """Produce a warning message."""
-        self.msg.warn(msg, context)
-
     def note(self, msg: str, context: Context, offset: int = 0) -> None:
         """Produce a note."""
         self.msg.note(msg, context, offset=offset)

mypy/errors.py

@@ -42,7 +42,7 @@ class ErrorInfo:
     # The column number related to this error with file.
     column = 0   # -1 if unknown
 
-    # Either 'error', 'note', or 'warning'.
+    # Either 'error' or 'note'
     severity = ''
 
     # The error message.
@@ -242,7 +242,7 @@ def report(self,
             line: line number of error
             message: message to report
             blocker: if True, don't continue analysis after this error
-            severity: 'error', 'note' or 'warning'
+            severity: 'error' or 'note'
             file: if non-None, override current file as context
             only_once: if True, only report this exact message once per build
             origin_line: if non-None, override current context as origin
@@ -314,13 +314,13 @@ def clear_errors_in_targets(self, path: str, targets: Set[str]) -> None:
                     self.only_once_messages.remove(info.message)
             self.error_info_map[path] = new_errors
 
-    def generate_unused_ignore_notes(self, file: str) -> None:
+    def generate_unused_ignore_errors(self, file: str) -> None:
         ignored_lines = self.ignored_lines[file]
         if not self.is_typeshed_file(file) and file not in self.ignored_files:
             for line in ignored_lines - self.used_ignored_lines[file]:
                 # Don't use report since add_error_info will ignore the error!
                 info = ErrorInfo(self.import_context(), file, self.current_module(), None,
-                                 None, line, -1, 'note', "unused 'type: ignore' comment",
+                                 None, line, -1, 'error', "unused 'type: ignore' comment",
                                  False, False)
                 self._add_error_info(file, info)
 

mypy/messages.py

@@ -142,11 +142,6 @@ def note_multiline(self, messages: str, context: Context, file: Optional[str] =
             self.report(msg, context, 'note', file=file, origin=origin,
                         offset=offset)
 
-    def warn(self, msg: str, context: Context, file: Optional[str] = None,
-             origin: Optional[Context] = None) -> None:
-        """Report a warning message (unless disabled)."""
-        self.report(msg, context, 'warning', file=file, origin=origin)
-
     def quote_type_string(self, type_string: str) -> str:
         """Quotes a type representation for use in messages."""
         no_quote_regex = r'^<(tuple|union): \d+ items>$'
@@ -1072,7 +1067,7 @@ def unsupported_type_type(self, item: Type, context: Context) -> None:
         self.fail('Unsupported type Type[{}]'.format(self.format(item)), context)
 
     def redundant_cast(self, typ: Type, context: Context) -> None:
-        self.note('Redundant cast to {}'.format(self.format(typ)), context)
+        self.fail('Redundant cast to {}'.format(self.format(typ)), context)
 
     def unimported_type_becomes_any(self, prefix: str, typ: Type, ctx: Context) -> None:
         self.fail("{} becomes {} due to an unfollowed import".format(prefix, self.format(typ)),
@@ -1163,7 +1158,7 @@ def disallowed_any_type(self, typ: Type, context: Context) -> None:
     def incorrectly_returning_any(self, typ: Type, context: Context) -> None:
         message = 'Returning Any from function declared to return {}'.format(
             self.format(typ))
-        self.warn(message, context)
+        self.fail(message, context)
 
     def untyped_decorated_function(self, typ: Type, context: Context) -> None:
         if isinstance(typ, AnyType):

test-data/unit/check-38.test

@@ -56,24 +56,24 @@ def g(x: int): ...
 
 [case testIgnoreScopeUnused1]
 # flags: --warn-unused-ignores
-(  # type: ignore  # N: unused 'type: ignore' comment
+(  # type: ignore  # E: unused 'type: ignore' comment
     "IGNORE"  # type: ignore
-    +  # type: ignore  # N: unused 'type: ignore' comment
-    0  # type: ignore  # N: unused 'type: ignore' comment
-)  # type: ignore  # N: unused 'type: ignore' comment
+    +  # type: ignore  # E: unused 'type: ignore' comment
+    0  # type: ignore  # E: unused 'type: ignore' comment
+)  # type: ignore  # E: unused 'type: ignore' comment
 
 [case testIgnoreScopeUnused2]
 # flags: --warn-unused-ignores
-(  # type: ignore  # N: unused 'type: ignore' comment
+(  # type: ignore  # E: unused 'type: ignore' comment
     "IGNORE"
     -  # type: ignore
-    0  # type: ignore  # N: unused 'type: ignore' comment
-)  # type: ignore  # N: unused 'type: ignore' comment
+    0  # type: ignore  # E: unused 'type: ignore' comment
+)  # type: ignore  # E: unused 'type: ignore' comment
 
 [case testIgnoreScopeUnused3]
 # flags: --warn-unused-ignores
-(  # type: ignore  # N: unused 'type: ignore' comment
+(  # type: ignore  # E: unused 'type: ignore' comment
     "IGNORE"
     /
     0  # type: ignore
-)  # type: ignore  # N: unused 'type: ignore' comment
+)  # type: ignore  # E: unused 'type: ignore' comment

test-data/unit/check-fastparse.test

@@ -319,10 +319,10 @@ def g():  # E: Type signature has too many arguments
 [case testFastParseMalformedAssert]
 
 assert 1, 2
-assert (1, 2)  # W: Assertion is always true, perhaps remove parentheses?
-assert (1, 2), 3  # W: Assertion is always true, perhaps remove parentheses?
+assert (1, 2)  # E: Assertion is always true, perhaps remove parentheses?
+assert (1, 2), 3  # E: Assertion is always true, perhaps remove parentheses?
 assert ()
-assert (1,)  # W: Assertion is always true, perhaps remove parentheses?
+assert (1,)  # E: Assertion is always true, perhaps remove parentheses?
 
 [case testFastParseAssertMessage]
 

test-data/unit/check-flags.test

@@ -286,7 +286,7 @@ def f() -> NoReturn:
 # flags: --warn-no-return
 from mypy_extensions import NoReturn
 
-def f() -> NoReturn:  # N: Implicit return in function which does not return
+def f() -> NoReturn:  # E: Implicit return in function which does not return
   non_trivial_function = 1
 [builtins fixtures/dict.pyi]
 
@@ -432,7 +432,7 @@ x + ""
 [file mod.py]
 deliberate syntax error
 [out]
-main:2: note: Import of 'mod' ignored
+main:2: error: Import of 'mod' ignored
 main:2: note: (Using --follow-imports=error, module not passed on command line)
 
 [case testIgnoreMissingImportsFalse]

test-data/unit/check-incremental.test

@@ -1783,10 +1783,10 @@ import a
 [file a.py.2]
 //
 [out1]
-main:2: note: Import of 'a' ignored
+main:2: error: Import of 'a' ignored
 main:2: note: (Using --follow-imports=error, module not passed on command line)
 [out2]
-main:2: note: Import of 'a' ignored
+main:2: error: Import of 'a' ignored
 main:2: note: (Using --follow-imports=error, module not passed on command line)
 
 [case testIncrementalFollowImportsVariable]

test-data/unit/check-modules.test

@@ -992,7 +992,7 @@ import mod
 [file mod.py]
 [builtins fixtures/module.pyi]
 [out]
-tmp/main.py:1: note: Import of 'mod' ignored
+tmp/main.py:1: error: Import of 'mod' ignored
 tmp/main.py:1: note: (Using --follow-imports=error, module not passed on command line)
 
 [case testAncestorSuppressedWhileAlmostSilent]
@@ -1002,7 +1002,7 @@ tmp/main.py:1: note: (Using --follow-imports=error, module not passed on command
 [file foo/__init__.py]
 [builtins fixtures/module.pyi]
 [out]
-tmp/foo/bar.py: note: Ancestor package 'foo' ignored
+tmp/foo/bar.py: error: Ancestor package 'foo' ignored
 tmp/foo/bar.py: note: (Using --follow-imports=error, submodule passed on command line)
 
 [case testStubImportNonStubWhileSilent]

test-data/unit/check-warnings.test

@@ -10,7 +10,7 @@ a = 1
 b = cast(str, a)
 c = cast(int, a)
 [out]
-main:5: note: Redundant cast to "int"
+main:5: error: Redundant cast to "int"
 
 [case testRedundantCastWithIsinstance]
 # flags: --warn-redundant-casts
@@ -20,7 +20,7 @@ if isinstance(x, str):
     cast(str, x)
 [builtins fixtures/isinstance.pyi]
 [out]
-main:5: note: Redundant cast to "str"
+main:5: error: Redundant cast to "str"
 
 [case testCastToSuperclassNotRedundant]
 # flags: --warn-redundant-casts
@@ -45,7 +45,7 @@ a = 1
 if int():
     a = 'a' # type: ignore
 if int():
-    a = 2 # type: ignore # N: unused 'type: ignore' comment
+    a = 2 # type: ignore # E: unused 'type: ignore' comment
 if int():
     a = 'b' # E: Incompatible types in assignment (expression has type "str", variable has type "int")
 
@@ -57,8 +57,8 @@ from m import * # type: ignore
 [file m.py]
 pass
 [out]
-main:3: note: unused 'type: ignore' comment
-main:4: note: unused 'type: ignore' comment
+main:3: error: unused 'type: ignore' comment
+main:4: error: unused 'type: ignore' comment
 
 
 -- No return
@@ -144,7 +144,7 @@ from typing import Any
 def g() -> Any: pass
 def f() -> int: return g()
 [out]
-main:4: warning: Returning Any from function declared to return "int"
+main:4: error: Returning Any from function declared to return "int"
 
 [case testReturnAnyForNotImplementedInBinaryMagicMethods]
 # flags: --warn-return-any
@@ -159,7 +159,7 @@ class A:
     def some(self) -> bool: return NotImplemented
 [builtins fixtures/notimplemented.pyi]
 [out]
-main:3: warning: Returning Any from function declared to return "bool"
+main:3: error: Returning Any from function declared to return "bool"
 
 [case testReturnAnyFromTypedFunctionWithSpecificFormatting]
 # flags: --warn-return-any
@@ -174,7 +174,7 @@ typ = Tuple[int, int, int, int, int, int, int, int, int, int, int, int, int,
 def g() -> Any: pass
 def f() -> typ: return g()
 [out]
-main:11: warning: Returning Any from function declared to return <tuple: 91 items>
+main:11: error: Returning Any from function declared to return <tuple: 91 items>
 
 [case testReturnAnySilencedFromTypedFunction]
 # flags: --warn-return-any