cmd/compile: remove Node.Nointerface field

We already keep the entire pragma bitset in n.Func.Pragma, so there's
no need to track Nointerface separately.

Passes toolstash -cmp.

Change-Id: Ic027ece477fcf63b0c1df128a08b89ef0f34fd58
Reviewed-on: https://go-review.googlesource.com/21381
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/gc/parser.go

@@ -1861,7 +1861,7 @@ func (p *parser) xfndcl() *Node {
 	}
 
 	p.want(LFUNC)
-	f := p.fndcl(p.pragma&Nointerface != 0)
+	f := p.fndcl()
 	body := p.fnbody()
 
 	if f == nil {
@@ -1886,7 +1886,7 @@ func (p *parser) xfndcl() *Node {
 // Function     = Signature FunctionBody .
 // MethodDecl   = "func" Receiver MethodName ( Function | Signature ) .
 // Receiver     = Parameters .
-func (p *parser) fndcl(nointerface bool) *Node {
+func (p *parser) fndcl() *Node {
 	if trace && Debug['x'] != 0 {
 		defer p.trace("fndcl")()
 	}
@@ -1950,7 +1950,6 @@ func (p *parser) fndcl(nointerface bool) *Node {
 		f.Func.Nname = methodname1(f.Func.Shortname, recv.Right)
 		f.Func.Nname.Name.Defn = f
 		f.Func.Nname.Name.Param.Ntype = t
-		f.Func.Nname.Nointerface = nointerface
 		declare(f.Func.Nname, PFUNC)
 
 		funchdr(f)

src/cmd/compile/internal/gc/syntax.go

@@ -50,7 +50,6 @@ type Node struct {
 	Esc uint16 // EscXXX
 
 	Op        Op
-	Nointerface bool
 	Ullman    uint8 // sethi/ullman number
 	Addable   bool  // addressable
 	Etype     EType // op for OASOP, etype for OTYPE, exclam for export, 6g saved reg

src/cmd/compile/internal/gc/typecheck.go

@@ -3423,7 +3423,7 @@ func typecheckfunc(n *Node) {
 	t.SetNname(n.Func.Nname)
 	rcvr := t.Recv()
 	if rcvr != nil && n.Func.Shortname != nil {
-		addmethod(n.Func.Shortname.Sym, t, nil, true, n.Func.Nname.Nointerface)
+		addmethod(n.Func.Shortname.Sym, t, nil, true, n.Func.Pragma&Nointerface != 0)
 	}
 
 	for _, ln := range n.Func.Dcl {