address bug193 and add note to spec about it.

R=ken
OCL=35920
CL=35920

doc/go_spec.html

@@ -9,6 +9,7 @@ Todo
     (struct{T} vs struct {T T} vs struct {t T})
 [ ] need explicit language about the result type of operations
 [ ] may want to have some examples for the types of shift operations
+[ ] should string(1<<s) and float(1<<s) be valid?
 [ ] should probably write something about evaluation order of statements even
 	though obvious
 [ ] specify iteration direction for range clause

src/cmd/gc/const.c

@@ -96,7 +96,7 @@ convlit1(Node **np, Type *t, int explicit)
 		break;
 	case OLSH:
 	case ORSH:
-		convlit(&n->left, t);
+		convlit1(&n->left, t, explicit);
 		t = n->left->type;
 		if(t != T && !isint[t->etype]) {
 			yyerror("invalid operation: %#N (shift of type %T)", n, t);

src/cmd/gc/subr.c

@@ -1455,11 +1455,12 @@ Zconv(Fmt *fp)
 		s += chartorune(&r, s);
 		switch(r) {
 		default:
+			if(r < ' ') {
+				fmtprint(fp, "\\x%02x", r);
+				break;
+			}
 			fmtrune(fp, r);
 			break;
-		case '\0':
-			fmtstrcpy(fp, "\\x00");
-			break;
 		case '\t':
 			fmtstrcpy(fp, "\\t");
 			break;

src/cmd/gc/typecheck.c

@@ -765,7 +765,7 @@ reswitch:
 	doconv:
 		ok |= Erv;
 		typecheck(&n->left, Erv | (top & Eindir));
-		defaultlit(&n->left, n->type);
+		convlit1(&n->left, n->type, 1);
 		if((t = n->left->type) == T || n->type == T)
 			goto error;
 		n = typecheckconv(n, n->left, n->type, 1);

test/bugs/placeholder

@@ -0,0 +1,2 @@
+This file keeps Mercurial from deleting the directory
+when there are no known bugs.

test/golden.out

@@ -201,6 +201,3 @@ throw: interface conversion
 panic PC=xxx
 
 == bugs/
-
-=========== bugs/bug193.go
-BUG: errchk: bugs/bug193.go:14: missing expected error: 'shift'

test/run

@@ -47,7 +47,7 @@ for dir in . ken chan interface nilptr fixedbugs bugs
 do
 	echo
 	echo '==' $dir'/'
-	for i in $dir/*.go
+	for i in $(ls $dir/*.go 2>/dev/null)
 	do
 		export F=$(basename $i .go)
 		export D=$dir
@@ -75,8 +75,9 @@ done | # clean up some stack noise
 	egrep -v '^(r[0-9a-z]+|[cfg]s)  +0x'  |
 	sed '/tmp.*Bus error/s/.*Bus/Bus/; /tmp.*Trace.BPT/s/.*Trace/Trace/
 		s!'$RUNFILE'!$RUNFILE!g
-		s/ PC=0x[0-9a-f]*/ PC=xxx/
+		s/^PC=0x[0-9a-f]*/pc: xxx/
 		s/^pc: 0x[0-9a-f]*/pc: xxx/
+		s/PC=0x[0-9a-f]*/PC=xxx/
 		/^Trace\/breakpoint trap/d
 		/^Trace\/BPT trap/d
 		/RUNFILE/ s/line 1: *[0-9]*/line 1: PID/