targs = append(targs, x.TypeParams().At(i))
			}
			smap := makeSubstMap(ytparams, targs)

			var check *Checker   // ok to call subst on a nil *Checker
			ctxt := NewContext() // need a non-nil Context for the substitution below

			// Constraints must be pair-wise identical, after substitution.
			for i, xtparam := range xtparams {
				ybound := check.subst(nopos, ytparams[i].bound, smap, nil, ctxt)

				targs = append(targs, x.TypeParams().At(i))
			}
			smap := makeSubstMap(ytparams, targs)

			var check *Checker   // ok to call subst on a nil *Checker
			ctxt := NewContext() // need a non-nil Context for the substitution below

			// Constraints must be pair-wise identical, after substitution.
			for i, xtparam := range xtparams {
				ybound := check.subst(nopos, ytparams[i].bound, smap, nil, ctxt)

	if !Vnamed || !Tnamed {
		return types.AssignableTo(V, T)
	}

	vtparams := VN.TypeParams()
	ttparams := TN.TypeParams()
	if vtparams.Len() == 0 || vtparams.Len() != ttparams.Len() || VN.TypeArgs().Len() != 0 || TN.TypeArgs().Len() != 0 {
		return types.AssignableTo(V, T)
	}

	// V and T have the same (non-zero) number of type params. Instantiate both
	// with the type parameters of V. This must always succeed for V, and will

	// example by renaming the type parameter P into P2.
	if len(tparams) == 0 {
		return nil, typ // nothing to do
	}

	tparams2 := make([]*TypeParam, len(tparams))
	for i, tparam := range tparams {
		tname := NewTypeName(tparam.Obj().Pos(), tparam.Obj().Pkg(), tparam.Obj().Name(), nil)
		tparams2[i] = NewTypeParam(tname, nil)
		tparams2[i].index = tparam.index // == i
	}

	renameMap := makeRenameMap(tparams, tparams2)

	// example by renaming the type parameter P into P2.
	if len(tparams) == 0 {
		return nil, typ // nothing to do
	}

	tparams2 := make([]*TypeParam, len(tparams))
	for i, tparam := range tparams {
		tname := NewTypeName(tparam.Obj().Pos(), tparam.Obj().Pkg(), tparam.Obj().Name(), nil)
		tparams2[i] = NewTypeParam(tname, nil)
		tparams2[i].index = tparam.index // == i
	}

	renameMap := makeRenameMap(tparams, tparams2)

}

func (r *reader) signature(recv *types.Var, rtparams, tparams []*types.TypeParam) *types.Signature {
	r.Sync(pkgbits.SyncSignature)

	params := r.params()
	results := r.params()
	variadic := r.Bool()

	return types.NewSignatureType(recv, rtparams, tparams, params, results, variadic)
}

func (r *reader) params() *types.Tuple {
	r.Sync(pkgbits.SyncParams)

	params := make([]*types.Var, r.Len())

		// are rare.)
		name := ""
		if len(params) > 0 && params[0].name != "" {
			// name needed
			name = sig.recv.name
			if name == "" {
				name = "_"
			}
		}
		params = append([]*Var{NewVar(sig.recv.pos, sig.recv.pkg, name, x.typ)}, params...)
		x.mode = value
		x.typ = &Signature{
			tparams:  sig.tparams,
			params:   NewTuple(params...),
			results:  sig.results,
			variadic: sig.variadic,

     *
     * @param params - the parameters to use during construction
     */
    void params(Object... params);

    /**
     * Sets any initialization parameters to use when constructing an instance of the implementation class.
     *
     * @param params - the parameters to use during construction
     */
    void setParams(Object... params);

    /**

    private final List<Object> params = new ArrayList<>();

    @Override
    public void params(Object... params) {
        Collections.addAll(this.params, params);
    }

    @Override
    public void setParams(Object... params) {
        this.params.clear();
        Collections.addAll(this.params, params);
    }

    @Override
    public Object[] getParams() {
        return this.params.toArray();
    }

		// are rare.)
		name := ""
		if len(params) > 0 && params[0].name != "" {
			// name needed
			name = sig.recv.name
			if name == "" {
				name = "_"
			}
		}
		params = append([]*Var{NewVar(sig.recv.pos, sig.recv.pkg, name, x.typ)}, params...)
		x.mode = value
		x.typ = &Signature{
			tparams:  sig.tparams,
			params:   NewTuple(params...),
			results:  sig.results,
			variadic: sig.variadic,