From 85815fe0ad000bc57366cd80057abe51da154ad3 Mon Sep 17 00:00:00 2001
From: Ken Thompson <ken@golang.org>
Date: Fri, 26 Dec 2008 14:42:20 -0800
Subject: [PATCH] diagnostic to catch pointer to rvalue promoted to method
 receiver. fixes to bignum that failed.

R=r
OCL=21827
CL=21827
---
 src/cmd/gc/walk.c      |  8 ++++++-
 src/lib/bignum.go      |  8 +++++--
 src/lib/bignum_test.go | 52 +++++++++++++++++++++++++++++++-----------
 3 files changed, 52 insertions(+), 16 deletions(-)

diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 58d24bca0b..6e04973009 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -1575,6 +1575,7 @@ lookdot(Node *n, Type *t)
 
 	if(f2 != T) {
 		if(needaddr(n->left->type)) {
+			walktype(n->left, Elv);
 			n->left = nod(OADDR, n->left, N);
 			n->left->type = ptrto(n->left->left->type);
 		}
@@ -2621,6 +2622,8 @@ arrayop(Node *n, int top)
 		// arrays2d(old *any, nel int) (ary []any)
 		t = fixarray(n->right->type);
 		tl = fixarray(n->left->type);
+		if(t == T || tl == T)
+			break;
 
 		a = nodintconst(t->bound);		// nel
 		a = nod(OCONV, a, N);
@@ -2642,6 +2645,8 @@ arrayop(Node *n, int top)
 	case ONEW:
 		// newarray(nel int, max int, width int) (ary []any)
 		t = fixarray(n->type);
+		if(t == T)
+			break;
 
 		a = nodintconst(t->type->width);	// width
 		a = nod(OCONV, a, N);
@@ -2679,6 +2684,8 @@ arrayop(Node *n, int top)
 		// arraysliced(old []any, lb int, hb int, width int) (ary []any)
 
 		t = fixarray(n->left->type);
+		if(t == T)
+			break;
 
 		a = nodintconst(t->type->width);	// width
 		a = nod(OCONV, a, N);
@@ -2693,7 +2700,6 @@ arrayop(Node *n, int top)
 		a->type = types[TINT];
 		r = list(a, r);
 
-		t = fixarray(n->left->type);
 		if(t->bound >= 0) {
 			// static slice
 			a = nodintconst(t->bound);		// nel
diff --git a/src/lib/bignum.go b/src/lib/bignum.go
index a4ea8c9732..cc4d4df89a 100755
--- a/src/lib/bignum.go
+++ b/src/lib/bignum.go
@@ -1261,8 +1261,12 @@ export func RatFromString(s string, base uint, slen *int) (*Rational, uint) {
 			alen++;
 			b, base = NatFromString(s[alen : len(s)], abase, &blen);
 			assert(base == abase);
-			f := Nat(base).Pow(uint(blen));
-			a = MakeInt(a.sign, a.mant.Mul(f).Add(b));
+			//BUG f := Nat(base).Pow(uint(blen));
+			na := Nat(base);
+			f := na.Pow(uint(blen));
+			//BUG a = MakeInt(a.sign, a.mant.Mul(f).Add(b));
+			nb := a.mant.Mul(f);
+			a = MakeInt(a.sign, nb.Add(b));
 			b = f;
 		}
 	}
diff --git a/src/lib/bignum_test.go b/src/lib/bignum_test.go
index af9538028e..510096c5ef 100644
--- a/src/lib/bignum_test.go
+++ b/src/lib/bignum_test.go
@@ -204,11 +204,19 @@ func Mul(x, y bignum.Natural) bignum.Natural {
 	if z1.Cmp(z2) != 0 {
 		tester.Fatalf("multiplication not symmetric:\n\tx = %v\n\ty = %t", x, y);
 	}
-	if !x.IsZero() && z1.Div(x).Cmp(y) != 0 {
-		tester.Fatalf("multiplication/division not inverse (A):\n\tx = %v\n\ty = %t", x, y);
+	// BUG if !x.IsZero() && z1.Div(x).Cmp(y) != 0 {
+	if !x.IsZero()  {
+		na := z1.Div(x);
+		if na.Cmp(y) != 0 {
+			tester.Fatalf("multiplication/division not inverse (A):\n\tx = %v\n\ty = %t", x, y);
+		}
 	}
-	if !y.IsZero() && z1.Div(y).Cmp(x) != 0 {
-		tester.Fatalf("multiplication/division not inverse (B):\n\tx = %v\n\ty = %t", x, y);
+	// BUG if !y.IsZero() && z1.Div(y).Cmp(x) != 0 {
+	if !y.IsZero() {
+		nb := z1.Div(y);
+		if nb.Cmp(x) != 0 {
+			tester.Fatalf("multiplication/division not inverse (B):\n\tx = %v\n\ty = %t", x, y);
+		}
 	}
 	return z1;
 }
@@ -243,7 +251,9 @@ export func TestNatMul(t *testing.T) {
 
 	test_msg = "NatMulC";
 	const n = 100;
-	p := b.Mul(c).Shl(n);
+	// BUG p := b.Mul(c).Shl(n);
+	na := b.Mul(c);
+	p := na.Shl(n);
 	for i := uint(0); i < n; i++ {
 		NAT_EQ(i, Mul(b.Shl(i), c.Shl(n-i)), p);
 	}
@@ -331,10 +341,16 @@ export func TestNatMod(t *testing.T) {
 	for i := uint(0); ; i++ {
 		d := nat_one.Shl(i);
 		if d.Cmp(c) < 0 {
-			NAT_EQ(i, c.Add(d).Mod(c), d);
+			//BUG NAT_EQ(i, c.Add(d).Mod(c), d);
+			na := c.Add(d);
+			NAT_EQ(i, na.Mod(c), d);
 		} else {
-			NAT_EQ(i, c.Add(d).Div(c), nat_two);
-			NAT_EQ(i, c.Add(d).Mod(c), d.Sub(c));
+			//BUG NAT_EQ(i, c.Add(d).Div(c), nat_two);
+			na := c.Add(d);
+			NAT_EQ(i, na.Div(c), nat_two);
+			//BUG NAT_EQ(i, c.Add(d).Mod(c), d.Sub(c));
+			nb := c.Add(d);
+			NAT_EQ(i, nb.Mod(c), d.Sub(c));
 			break;
 		}
 	}
@@ -444,12 +460,18 @@ export func TestNatLog2(t *testing.T) {
 	test_msg = "NatLog2A";
 	TEST(0, nat_one.Log2() == 0);
 	TEST(1, nat_two.Log2() == 1);
-	TEST(2, bignum.Nat(3).Log2() == 1);
-	TEST(3, bignum.Nat(4).Log2() == 2);
+	//BUG TEST(2, bignum.Nat(3).Log2() == 1);
+	na := bignum.Nat(3);
+	TEST(2, na.Log2() == 1);
+	//BUG TEST(3, bignum.Nat(4).Log2() == 2);
+	nb := bignum.Nat(4);
+	TEST(3, nb.Log2() == 2);
 	
 	test_msg = "NatLog2B";
 	for i := uint(0); i < 100; i++ {
-		TEST(i, nat_one.Shl(i).Log2() == i);
+		//BUG TEST(i, nat_one.Shl(i).Log2() == i);
+		nc := nat_one.Shl(i);
+		TEST(i, nc.Log2() == i);
 	}
 }
 
@@ -484,8 +506,12 @@ export func TestNatPop(t *testing.T) {
 	test_msg = "NatPopA";
 	TEST(0, nat_zero.Pop() == 0);
 	TEST(1, nat_one.Pop() == 1);
-	TEST(2, bignum.Nat(10).Pop() == 2);
-	TEST(3, bignum.Nat(30).Pop() == 4);
+	//BUG TEST(2, bignum.Nat(10).Pop() == 2);
+	na := bignum.Nat(10);
+	TEST(2, na.Pop() == 2);
+	//BUG TEST(3, bignum.Nat(30).Pop() == 4);
+	nb := bignum.Nat(30);
+	TEST(3, nb.Pop() == 4);
 	// BUG TEST(4, bignum.Nat(0x1248f).Shl(33).Pop() == 8);
 	g := bignum.Nat(0x1248f);
 	g = g.Shl(33);