check all statements of the relevant if or else block instead of only the first one (which allows to call is_noop_for_reachability).

Author: tyralla

mypy/checker.py

@@ -5054,19 +5054,7 @@ def _visit_if_stmt_redundant_expr_helper(
         def _filter(body: Block | None) -> bool:
             if body is None:
                 return False
-            s = body.body[0]
-            if isinstance(s, AssertStmt) and is_false_literal(s.expr):
-                return True
-            if isinstance(s, RaiseStmt):
-                return True
-            elif isinstance(s, ExpressionStmt) and isinstance(s.expr, CallExpr):
-                with self.expr_checker.msg.filter_errors(filter_revealed_type=True):
-                    typ = self.expr_checker.accept(
-                        s.expr, allow_none_return=True, always_allow_any=True
-                    )
-                if isinstance(get_proper_type(typ), UninhabitedType):
-                    return True
-            return False
+            return all(self.is_noop_for_reachability(s) for s in body.body)
 
         if if_map is None:
             if stmt.while_stmt:

test-data/unit/check-isinstance.test

@@ -3137,4 +3137,21 @@ def f6(x: Literal[1]) -> None:
     if x != 1:
         raise ValueError
 
+def f7(x: Literal[1, 2]) -> None:
+    if x == 1:
+        y = "a"
+    elif x == 2:
+        y = "b"
+    else:
+        pass
+
+def f8(x: Literal[1, 2]) -> None:
+    if x == 1:
+        y = "a"
+    elif x == 2:  # E: If condition is always true
+        y = "b"
+    else:
+        pass
+        y = "c"
+
 [builtins fixtures/bool.pyi]