Function getRestrictiveTypeParameter

test/fixtures/snapshot/typescript.js:63337–63341

(tp)

            return !mapper ? makeUnaryTypeMapper(source, target) : makeCompositeTypeMapper(4 /* TypeMapKind.Merged */, mapper, makeUnaryTypeMapper(source, target));
        }
        function getRestrictiveTypeParameter(tp) {
            return tp.constraint === unknownType ? tp : tp.restrictiveInstantiation || (tp.restrictiveInstantiation = createTypeParameter(tp.symbol),
                tp.restrictiveInstantiation.constraint = unknownType,
                tp.restrictiveInstantiation);
        }
        function cloneTypeParameter(typeParameter) {
            var result = createTypeParameter(typeParameter.symbol);
            result.target = typeParameter;