UndefinedConcreteTypeError
UndefinedVarByOpViolation
UndefinedVariableDefinitionViolation
UnionTypeAstDirectiveAdded
UnionTypeAstDirectiveRemoved
UnionTypeExtensionDefinition
UniqueDirectivesPerLocation
UnknownDirectiveArgViolation
UnknownDirectiveViolation
UnknownInputObjectFieldViolation
UnknownVariableTypeViolation
useLegacyCommentDescriptions