Don't typecheck unreachable noops

Author: A5rocks

mypy/checker.py

@@ -480,6 +480,9 @@ def check_first_pass(self) -> None:
                                 if not self.options.check_unreachable:
                                     break
 
+                            if not self.options.check_unreachable:
+                                continue
+
                         self.accept(d)
 
                 assert not self.current_node_deferred
@@ -3145,6 +3148,10 @@ def visit_block(self, b: Block) -> None:
                     if not self.options.check_unreachable:
                         break
 
+                if not self.options.check_unreachable:
+                    # skip checking *anything*, even if it's a noop
+                    continue
+
             self.accept(s)
 
     def should_report_unreachable_issues(self) -> bool: