anchor.diff:          declaredFormal.isCovariant = true;
           if (declaredFormal.formalSafety != FormalSafety.unsafe) {
             declaredFormal.formalSafety = FormalSafety.unsafe;
  -          instrumentation?.record(
  -              Uri.parse(cls.fileUri),
  -              declaredFormal.fileOffset,
  -              'checkFormal',
  -              new InstrumentationValueLiteral('unsafe'));
           }
         }
         if (declaredIsAbstract) return;
  
positive.code:         }
        }
      });
    }
  
    /// Creates an [AccessorNode] to track dependencies of the given [member].
  
negative.code:         addDeclaredAdditionalIncomingType(incomingType);
          if (formalSafety == FormalSafety.safe) {
            setFormalSafety(FormalSafety.semiSafe);
          }
        }
      }
  