You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: typeparam.go
    path of file: ./repos/gccrs/libgo/go/go/types
    
    the code of the file until where you have to start completion: // Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// lice
    
func (t *TypeParam) iface() *Interface {
	bound := t.bound

	// determine constraint interface
	var ityp *Interface
	switch u := under(bound).(type) {
	case *Basic:
		if u == Typ[Invalid] {
			// error is reported elsewhere
			return &emptyInterface
		}
	case *Interface:
		if isTypeParam(bound) {
			// error is reported in Checker.collectTypeParams
			return &emptyInterface
		}
		ityp = u
	}

	// If we don't have an interface, wrap constraint into an implicit interface.
	if ityp == nil {
		ityp = NewInterfaceType(nil, []Type{bound})
		ityp.implicit = true
		t.bound = ityp // update t.bound for next time (optimization)
	}

	// compute type set if necessary
	if ityp.tset == nil {
		// pos is used for tracing output; start with the type parameter position.
		pos := t.obj.pos
		// use the (original or possibly instantiated) type bound position if we have one
		if n, _ := bound.(*Named); n != nil {
			pos = n.obj.pos
		}
		computeInterfaceTypeSet(t.check, pos, ityp)
	}

	return ityp
}