disallow P.t for lowercase t and not our package P.

implement hiding lowercase methods m in
signatures by adding in a hash of the package name
to the type hash code.

remove remaining checks for internally-generated _ names:
they are all gone.

R=ken
OCL=23236
CL=23238

src/cmd/6g/gen.c

@@ -57,9 +57,8 @@ if(throwreturn == N) {
 		// add clearing of the output parameters
 		t = structfirst(&save, getoutarg(curfn->type));
 		while(t != T) {
-			if(t->nname != N && t->nname->sym->name[0] != '_') {
+			if(t->nname != N)
 				curfn->nbody = list(nod(OAS, t->nname, N), curfn->nbody);
-			}
 			t = structnext(&save);
 		}
 	}

src/cmd/6g/obj.c

@@ -658,6 +658,8 @@ dumpsigt(Type *progt, Type *ifacet, Type *rcvrt, Type *methodt, Sym *s)
 
 		a->name = method->name;
 		a->hash = PRIME8*stringhash(a->name) + PRIME9*typehash(f->type, 0);
+		if(!exportname(a->name))
+			a->hash += PRIME10*stringhash(package);
 		a->perm = o;
 		a->sym = methodsym(method, rcvrt);
 
@@ -767,7 +769,6 @@ dumpsigi(Type *t, Sym *s)
 	int o;
 	Sig *a, *b;
 	Prog *p;
-	char *sp;
 	char buf[NSYMB];
 
 	at.sym = s;
@@ -784,19 +785,15 @@ dumpsigi(Type *t, Sym *s)
 		s1 = f->sym;
 		if(s1 == nil)
 			continue;
-		if(s1->name[0] == '_')
-			continue;
 
 		b = mal(sizeof(*b));
 		b->link = a;
 		a = b;
 
 		a->name = s1->name;
-		sp = strchr(s1->name, '_');
-		if(sp != nil)
-			a->name = sp+1;
-
 		a->hash = PRIME8*stringhash(a->name) + PRIME9*typehash(f->type, 0);
+		if(!exportname(a->name))
+			a->hash += PRIME10*stringhash(package);
 		a->perm = o;
 		a->sym = methodsym(f->sym, t);
 		a->offset = 0;

src/cmd/gc/dcl.c

@@ -433,7 +433,7 @@ funcargs(Type *ft)
 	while(t != T) {
 		if(t->nname != N)
 			t->nname->xoffset = t->width;
-		if(t->nname != N && t->nname->sym->name[0] != '_') {
+		if(t->nname != N) {
 			addvar(t->nname, t->type, PPARAM);
 			all |= 1;
 		} else

src/cmd/gc/go.h

@@ -34,6 +34,7 @@ enum
 	PRIME7		= 10067,
 	PRIME8		= 10079,
 	PRIME9		= 10091,
+	PRIME10		= 10093,
 
 	AUNK		= 100,
 	// these values are known by runtime

src/cmd/gc/lex.c

@@ -685,6 +685,8 @@ talph:
 		s = pkglookup(s->name, context);
 		if(s->lexical == LIGNORE)
 			goto l0;
+		if(!exportname(s->name) && strcmp(package, s->opackage) != 0)
+			s = pkglookup(s->name, ".private");
 	}
 
 	DBG("lex: %S %s\n", s, lexname(s->lexical));

src/cmd/gc/subr.c

@@ -1683,12 +1683,8 @@ eqtype(Type *t1, Type *t2, int d)
 			if(t1->nname != N && t1->nname->sym != S) {
 				if(t2->nname == N || t2->nname->sym == S)
 					return 0;
-				if(strcmp(t1->nname->sym->name, t2->nname->sym->name) != 0) {
-					// assigned names dont count
-					if(t1->nname->sym->name[0] != '_' ||
-				   	   t2->nname->sym->name[0] != '_')
-						return 0;
-				}
+				if(strcmp(t1->nname->sym->name, t2->nname->sym->name) != 0)
+					return 0;
 			}
 			t1 = t1->down;
 			t2 = t2->down;
@@ -2489,7 +2485,7 @@ expand0(Type *t)
 	u = methtype(t);
 	if(u != T) {
 		for(f=u->method; f!=T; f=f->down) {
-			if(!exportname(f->sym->name) && strcmp(f->sym->package, package) != 0)
+			if(!exportname(f->sym->name) && strcmp(f->sym->opackage, package) != 0)
 				continue;
 			if(f->sym->uniq)
 				continue;

src/runtime/iface.c

@@ -168,6 +168,13 @@ throw:
 					prints(": missing method ");
 					prints((int8*)iname);
 					prints("\n");
+					if(iface_debug) {
+						prints("interface");
+						printsigi(si);
+						prints("\ntype");
+						printsigt(st);
+						prints("\n");
+					}
 					throw("interface conversion");
 				}
 				m->bad = 1;

test/golden.out

@@ -232,7 +232,7 @@ fixedbugs/bug074.go:7: x: undefined
 fixedbugs/bug081.go:5: no type x
 
 =========== fixedbugs/bug083.go
-BUG: succeeds incorrectly
+fixedbugs/bug083.dir/bug1.go:9: syntax error near t0
 
 =========== fixedbugs/bug086.go
 fixedbugs/bug086.go:5: function ends without a return statement