Use new --enable-error-codes functionlity

Author: llchan

mypy/checkexpr.py

@@ -2747,7 +2747,7 @@ def check_boolean_op(self, e: OpExpr, context: Context) -> Type:
         # the analysis from the semanal phase below. We assume that nodes
         # marked as unreachable during semantic analysis were done so intentionally.
         # So, we shouldn't report an error.
-        if self.chk.options.warn_redundant_expr:
+        if codes.REDUNDANT_EXPR in self.chk.options.enabled_error_codes:
             if left_map is None:
                 self.msg.redundant_left_operand(e.op, e.left)
 
@@ -3682,7 +3682,7 @@ def check_for_comp(self, e: Union[GeneratorExpr, DictionaryComprehension]) -> No
                     for var, type in true_map.items():
                         self.chk.binder.put(var, type)
 
-                if self.chk.options.warn_redundant_expr:
+                if codes.REDUNDANT_EXPR in self.chk.options.enabled_error_codes:
                     if true_map is None:
                         self.msg.redundant_condition_in_comprehension(False, condition)
                     elif false_map is None:
@@ -3695,7 +3695,7 @@ def visit_conditional_expr(self, e: ConditionalExpr, allow_none_return: bool = F
         # Gain type information from isinstance if it is there
         # but only for the current expression
         if_map, else_map = self.chk.find_isinstance_check(e.cond)
-        if self.chk.options.warn_redundant_expr:
+        if codes.REDUNDANT_EXPR in self.chk.options.enabled_error_codes:
             if if_map is None:
                 self.msg.redundant_condition_in_if(False, e.cond)
             elif else_map is None:

mypy/main.py

@@ -578,9 +578,6 @@ def add_invertible_flag(flag: str,
                         help="Warn about statements or expressions inferred to be"
                              " unreachable",
                         group=lint_group)
-    add_invertible_flag('--warn-redundant-expr', default=False, strict_flag=False,
-                        help="Warn about expressions inferred to be redundant",
-                        group=lint_group)
 
     # Note: this group is intentionally added here even though we don't add
     # --strict to this group near the end.

mypy/options.py

@@ -51,7 +51,6 @@ class BuildType:
     "strict_optional_whitelist",
     "warn_no_return",
     "warn_return_any",
-    "warn_redundant_expr",
     "warn_unreachable",
     "warn_unused_ignores",
 }  # type: Final
@@ -175,10 +174,6 @@ def __init__(self) -> None:
         # type analysis.
         self.warn_unreachable = False
 
-        # Report an error for any expressions inferred to be redundant as a result of
-        # type analysis.
-        self.warn_redundant_expr = False
-
         # Variable names considered True
         self.always_true = []  # type: List[str]
 

test-data/unit/check-redundant-expr.test

@@ -2,7 +2,7 @@
 -- expressions classified as redundant.
 
 [case testRedundantExpressions]
-# flags: --warn-redundant-expr
+# flags: --enable-error-code redundant-expr
 def foo() -> bool: ...
 
 lst = [1, 2, 3, 4]