[dev.typeparams] cmd/compile: simplify ~r/~b naming

The compiler renames anonymous and blank result parameters to ~rN or
~bN, but the current semantics for computing N are rather annoying and
difficult to reproduce cleanly. They also lead to difficult to read
escape analysis results in tests.

This CL changes N to always be calculated as the parameter's index
within the function's result parameter tuple. E.g., if a function has
a single result, it will now always be named "~r0".

The normative change to this CL is fairly simple, but it requires
updating a lot of test expectations.

Change-Id: I58a3c94de00cb822cb94efe52d115531193c993c
Reviewed-on: https://go-review.googlesource.com/c/go/+/323010
Trust: Matthew Dempsky <mdempsky@google.com>
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>

17 files changed, 101 insertions, 102 deletions

diff --git a/src/cmd/compile/internal/logopt/logopt_test.go b/src/cmd/compile/internal/logopt/logopt_test.go
index 71976174b0..41a11b0c70 100644
--- a/src/cmd/compile/internal/logopt/logopt_test.go
+++ b/src/cmd/compile/internal/logopt/logopt_test.go
@@ -209,7 +209,7 @@ func s15a8(x *[15]int64) [15]int64 {
 		want(t, slogged, `{"range":{"start":{"line":11,"character":6},"end":{"line":11,"character":6}},"severity":3,"code":"isInBounds","source":"go compiler","message":""}`)
 		want(t, slogged, `{"range":{"start":{"line":7,"character":6},"end":{"line":7,"character":6}},"severity":3,"code":"canInlineFunction","source":"go compiler","message":"cost: 35"}`)
 		// escape analysis explanation
-		want(t, slogged, `{"range":{"start":{"line":7,"character":13},"end":{"line":7,"character":13}},"severity":3,"code":"leak","source":"go compiler","message":"parameter z leaks to ~r2 with derefs=0",`+
+		want(t, slogged, `{"range":{"start":{"line":7,"character":13},"end":{"line":7,"character":13}},"severity":3,"code":"leak","source":"go compiler","message":"parameter z leaks to ~r0 with derefs=0",`+
 			`"relatedInformation":[`+
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":13},"end":{"line":9,"character":13}}},"message":"escflow:    flow: y = z:"},`+
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":13},"end":{"line":9,"character":13}}},"message":"escflow:      from y := z (assign-pair)"},`+
@@ -220,7 +220,7 @@ func s15a8(x *[15]int64) [15]int64 {
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":13},"end":{"line":9,"character":13}}},"message":"escflow:      from \u0026y.b (address-of)"},`+
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":4,"character":9},"end":{"line":4,"character":9}}},"message":"inlineLoc"},`+
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":13},"end":{"line":9,"character":13}}},"message":"escflow:      from ~R0 = \u0026y.b (assign-pair)"},`+
-			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":3},"end":{"line":9,"character":3}}},"message":"escflow:    flow: ~r2 = ~R0:"},`+
+			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":3},"end":{"line":9,"character":3}}},"message":"escflow:    flow: ~r0 = ~R0:"},`+
 			`{"location":{"uri":"file://tmpdir/file.go","range":{"start":{"line":9,"character":3},"end":{"line":9,"character":3}}},"message":"escflow:      from return (*int)(~R0) (return)"}]}`)
 	})
 }
diff --git a/src/cmd/compile/internal/noder/object.go b/src/cmd/compile/internal/noder/object.go
index a1a10e4eaa..581a3652ec 100644
--- a/src/cmd/compile/internal/noder/object.go
+++ b/src/cmd/compile/internal/noder/object.go
@@ -113,19 +113,21 @@ func (g *irgen) obj(obj types2.Object) *ir.Name {
 		}
 
 	case *types2.Var:
-		var sym *types.Sym
-		if class == ir.PPARAMOUT {
+		sym := g.sym(obj)
+		if class == ir.PPARAMOUT && (sym == nil || sym.IsBlank()) {
 			// Backend needs names for result parameters,
 			// even if they're anonymous or blank.
-			switch obj.Name() {
-			case "":
-				sym = typecheck.LookupNum("~r", len(ir.CurFunc.Dcl)) // 'r' for "result"
-			case "_":
-				sym = typecheck.LookupNum("~b", len(ir.CurFunc.Dcl)) // 'b' for "blank"
+			nresults := 0
+			for _, n := range ir.CurFunc.Dcl {
+				if n.Class == ir.PPARAMOUT {
+					nresults++
+				}
+			}
+			if sym == nil {
+				sym = typecheck.LookupNum("~r", nresults) // 'r' for "result"
+			} else {
+				sym = typecheck.LookupNum("~b", nresults) // 'b' for "blank"
 			}
-		}
-		if sym == nil {
-			sym = g.sym(obj)
 		}
 		name = g.objCommon(pos, ir.ONAME, sym, class, g.typ(obj.Type()))
 
diff --git a/src/cmd/compile/internal/typecheck/dcl.go b/src/cmd/compile/internal/typecheck/dcl.go
index f3058d8811..5f8b8b3d41 100644
--- a/src/cmd/compile/internal/typecheck/dcl.go
+++ b/src/cmd/compile/internal/typecheck/dcl.go
@@ -353,12 +353,10 @@ func funcargs(nt *ir.FuncType) {
 	}
 
 	// declare the out arguments.
-	gen := len(nt.Params)
-	for _, n := range nt.Results {
+	for i, n := range nt.Results {
 		if n.Sym == nil {
 			// Name so that escape analysis can track it. ~r stands for 'result'.
-			n.Sym = LookupNum("~r", gen)
-			gen++
+			n.Sym = LookupNum("~r", i)
 		}
 		if n.Sym.IsBlank() {
 			// Give it a name so we can assign to it during return. ~b stands for 'blank'.
@@ -367,8 +365,7 @@ func funcargs(nt *ir.FuncType) {
 			//	func g() int
 			// f is allowed to use a plain 'return' with no arguments, while g is not.
 			// So the two cases must be distinguished.
-			n.Sym = LookupNum("~b", gen)
-			gen++
+			n.Sym = LookupNum("~b", i)
 		}
 
 		funcarg(n, ir.PPARAMOUT)
diff --git a/test/escape2.go b/test/escape2.go
index b9b723d866..04ab635aa5 100644
--- a/test/escape2.go
+++ b/test/escape2.go
@@ -59,7 +59,7 @@ func foo8(xx, yy *int) int { // ERROR "xx does not escape$" "yy does not escape$
 	return *xx
 }
 
-func foo9(xx, yy *int) *int { // ERROR "leaking param: xx to result ~r2 level=0$" "leaking param: yy to result ~r2 level=0$"
+func foo9(xx, yy *int) *int { // ERROR "leaking param: xx to result ~r0 level=0$" "leaking param: yy to result ~r0 level=0$"
 	xx = yy
 	return xx
 }
@@ -343,11 +343,11 @@ func indaddr1(x int) *int { // ERROR "moved to heap: x$"
 	return &x
 }
 
-func indaddr2(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0$"
+func indaddr2(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0$"
 	return *&x
 }
 
-func indaddr3(x *int32) *int { // ERROR "leaking param: x to result ~r1 level=0$"
+func indaddr3(x *int32) *int { // ERROR "leaking param: x to result ~r0 level=0$"
 	return *(**int)(unsafe.Pointer(&x))
 }
 
@@ -374,11 +374,11 @@ func float64bitsptr(f float64) *uint64 { // ERROR "moved to heap: f$"
 	return (*uint64)(unsafe.Pointer(&f))
 }
 
-func float64ptrbitsptr(f *float64) *uint64 { // ERROR "leaking param: f to result ~r1 level=0$"
+func float64ptrbitsptr(f *float64) *uint64 { // ERROR "leaking param: f to result ~r0 level=0$"
 	return (*uint64)(unsafe.Pointer(f))
 }
 
-func typesw(i interface{}) *int { // ERROR "leaking param: i to result ~r1 level=0$"
+func typesw(i interface{}) *int { // ERROR "leaking param: i to result ~r0 level=0$"
 	switch val := i.(type) {
 	case *int:
 		return val
@@ -389,7 +389,7 @@ func typesw(i interface{}) *int { // ERROR "leaking param: i to result ~r1 level
 	return nil
 }
 
-func exprsw(i *int) *int { // ERROR "leaking param: i to result ~r1 level=0$"
+func exprsw(i *int) *int { // ERROR "leaking param: i to result ~r0 level=0$"
 	switch j := i; *j + 110 {
 	case 12:
 		return j
@@ -401,7 +401,7 @@ func exprsw(i *int) *int { // ERROR "leaking param: i to result ~r1 level=0$"
 }
 
 // assigning to an array element is like assigning to the array
-func foo60(i *int) *int { // ERROR "leaking param: i to result ~r1 level=0$"
+func foo60(i *int) *int { // ERROR "leaking param: i to result ~r0 level=0$"
 	var a [12]*int
 	a[0] = i
 	return a[1]
@@ -414,7 +414,7 @@ func foo60a(i *int) *int { // ERROR "i does not escape$"
 }
 
 // assigning to a struct field  is like assigning to the struct
-func foo61(i *int) *int { // ERROR "leaking param: i to result ~r1 level=0$"
+func foo61(i *int) *int { // ERROR "leaking param: i to result ~r0 level=0$"
 	type S struct {
 		a, b *int
 	}
@@ -611,11 +611,11 @@ func foo74c() {
 	}
 }
 
-func myprint(y *int, x ...interface{}) *int { // ERROR "leaking param: y to result ~r2 level=0$" "x does not escape$"
+func myprint(y *int, x ...interface{}) *int { // ERROR "leaking param: y to result ~r0 level=0$" "x does not escape$"
 	return y
 }
 
-func myprint1(y *int, x ...interface{}) *interface{} { // ERROR "leaking param: x to result ~r2 level=0$" "y does not escape$"
+func myprint1(y *int, x ...interface{}) *interface{} { // ERROR "leaking param: x to result ~r0 level=0$" "y does not escape$"
 	return &x[0]
 }
 
@@ -770,7 +770,7 @@ func foo91(x *int) map[*int]*int { // ERROR "leaking param: x$"
 	return map[*int]*int{x: nil} // ERROR "map\[\*int\]\*int{...} escapes to heap$"
 }
 
-func foo92(x *int) [2]*int { // ERROR "leaking param: x to result ~r1 level=0$"
+func foo92(x *int) [2]*int { // ERROR "leaking param: x to result ~r0 level=0$"
 	return [2]*int{x, nil}
 }
 
@@ -783,7 +783,7 @@ func foo93(c chan *int) *int { // ERROR "c does not escape$"
 }
 
 // does not leak m
-func foo94(m map[*int]*int, b bool) *int { // ERROR "leaking param: m to result ~r2 level=1"
+func foo94(m map[*int]*int, b bool) *int { // ERROR "leaking param: m to result ~r0 level=1"
 	for k, v := range m {
 		if b {
 			return k
@@ -799,12 +799,12 @@ func foo95(m map[*int]*int, x *int) { // ERROR "m does not escape$" "leaking par
 }
 
 // does not leak m but does leak content
-func foo96(m []*int) *int { // ERROR "leaking param: m to result ~r1 level=1"
+func foo96(m []*int) *int { // ERROR "leaking param: m to result ~r0 level=1"
 	return m[0]
 }
 
 // does leak m
-func foo97(m [1]*int) *int { // ERROR "leaking param: m to result ~r1 level=0$"
+func foo97(m [1]*int) *int { // ERROR "leaking param: m to result ~r0 level=0$"
 	return m[0]
 }
 
@@ -814,12 +814,12 @@ func foo98(m map[int]*int) *int { // ERROR "m does not escape$"
 }
 
 // does leak m
-func foo99(m *[1]*int) []*int { // ERROR "leaking param: m to result ~r1 level=0$"
+func foo99(m *[1]*int) []*int { // ERROR "leaking param: m to result ~r0 level=0$"
 	return m[:]
 }
 
 // does not leak m
-func foo100(m []*int) *int { // ERROR "leaking param: m to result ~r1 level=1"
+func foo100(m []*int) *int { // ERROR "leaking param: m to result ~r0 level=1"
 	for _, v := range m {
 		return v
 	}
@@ -827,7 +827,7 @@ func foo100(m []*int) *int { // ERROR "leaking param: m to result ~r1 level=1"
 }
 
 // does leak m
-func foo101(m [1]*int) *int { // ERROR "leaking param: m to result ~r1 level=0$"
+func foo101(m [1]*int) *int { // ERROR "leaking param: m to result ~r0 level=0$"
 	for _, v := range m {
 		return v
 	}
@@ -890,27 +890,27 @@ func foo110(x *int) *int { // ERROR "leaking param: x$"
 	return m[nil]
 }
 
-func foo111(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0"
+func foo111(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0"
 	m := []*int{x} // ERROR "\[\]\*int{...} does not escape$"
 	return m[0]
 }
 
-func foo112(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0$"
+func foo112(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0$"
 	m := [1]*int{x}
 	return m[0]
 }
 
-func foo113(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0$"
+func foo113(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0$"
 	m := Bar{ii: x}
 	return m.ii
 }
 
-func foo114(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0$"
+func foo114(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0$"
 	m := &Bar{ii: x} // ERROR "&Bar{...} does not escape$"
 	return m.ii
 }
 
-func foo115(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0$"
+func foo115(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0$"
 	return (*int)(unsafe.Pointer(uintptr(unsafe.Pointer(x)) + 1))
 }
 
diff --git a/test/escape2n.go b/test/escape2n.go
index 7c8208aa73..01a25795f4 100644
--- a/test/escape2n.go
+++ b/test/escape2n.go
@@ -59,7 +59,7 @@ func foo8(xx, yy *int) int { // ERROR "xx does not escape$" "yy does not escape$
 	return *xx
 }
 
-func foo9(xx, yy *int) *int { // ERROR "leaking param: xx to result ~r2 level=0$" "leaking param: yy to result ~r2 level=0$"
+func foo9(xx, yy *int) *int { // ERROR "leaking param: xx to result ~r0 level=0$" "leaking param: yy to result ~r0 level=0$"
 	xx = yy
 	return xx
 }
@@ -343,11 +343,11 @@ func indaddr1(x int) *int { // ERROR "moved to heap: x$"
 	return &x
 }
 
-func indaddr2(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0$"
+func indaddr2(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0$"
 	return *&x
 }
 
-func indaddr3(x *int32) *int { // ERROR "leaking param: x to result ~r1 level=0$"
+func indaddr3(x *int32) *int { // ERROR "leaking param: x to result ~r0 level=0$"
 	return *(**int)(unsafe.Pointer(&x))
 }
 
@@ -374,11 +374,11 @@ func float64bitsptr(f float64) *uint64 { // ERROR "moved to heap: f$"
 	return (*uint64)(unsafe.Pointer(&f))
 }
 
-func float64ptrbitsptr(f *float64) *uint64 { // ERROR "leaking param: f to result ~r1 level=0$"
+func float64ptrbitsptr(f *float64) *uint64 { // ERROR "leaking param: f to result ~r0 level=0$"
 	return (*uint64)(unsafe.Pointer(f))
 }
 
-func typesw(i interface{}) *int { // ERROR "leaking param: i to result ~r1 level=0$"
+func typesw(i interface{}) *int { // ERROR "leaking param: i to result ~r0 level=0$"
 	switch val := i.(type) {
 	case *int:
 		return val
@@ -389,7 +389,7 @@ func typesw(i interface{}) *int { // ERROR "leaking param: i to result ~r1 level
 	return nil
 }
 
-func exprsw(i *int) *int { // ERROR "leaking param: i to result ~r1 level=0$"
+func exprsw(i *int) *int { // ERROR "leaking param: i to result ~r0 level=0$"
 	switch j := i; *j + 110 {
 	case 12:
 		return j
@@ -401,7 +401,7 @@ func exprsw(i *int) *int { // ERROR "leaking param: i to result ~r1 level=0$"
 }
 
 // assigning to an array element is like assigning to the array
-func foo60(i *int) *int { // ERROR "leaking param: i to result ~r1 level=0$"
+func foo60(i *int) *int { // ERROR "leaking param: i to result ~r0 level=0$"
 	var a [12]*int
 	a[0] = i
 	return a[1]
@@ -414,7 +414,7 @@ func foo60a(i *int) *int { // ERROR "i does not escape$"
 }
 
 // assigning to a struct field  is like assigning to the struct
-func foo61(i *int) *int { // ERROR "leaking param: i to result ~r1 level=0$"
+func foo61(i *int) *int { // ERROR "leaking param: i to result ~r0 level=0$"
 	type S struct {
 		a, b *int
 	}
@@ -611,11 +611,11 @@ func foo74c() {
 	}
 }
 
-func myprint(y *int, x ...interface{}) *int { // ERROR "leaking param: y to result ~r2 level=0$" "x does not escape$"
+func myprint(y *int, x ...interface{}) *int { // ERROR "leaking param: y to result ~r0 level=0$" "x does not escape$"
 	return y
 }
 
-func myprint1(y *int, x ...interface{}) *interface{} { // ERROR "leaking param: x to result ~r2 level=0$" "y does not escape$"
+func myprint1(y *int, x ...interface{}) *interface{} { // ERROR "leaking param: x to result ~r0 level=0$" "y does not escape$"
 	return &x[0]
 }
 
@@ -770,7 +770,7 @@ func foo91(x *int) map[*int]*int { // ERROR "leaking param: x$"
 	return map[*int]*int{x: nil} // ERROR "map\[\*int\]\*int{...} escapes to heap$"
 }
 
-func foo92(x *int) [2]*int { // ERROR "leaking param: x to result ~r1 level=0$"
+func foo92(x *int) [2]*int { // ERROR "leaking param: x to result ~r0 level=0$"
 	return [2]*int{x, nil}
 }
 
@@ -783,7 +783,7 @@ func foo93(c chan *int) *int { // ERROR "c does not escape$"
 }
 
 // does not leak m
-func foo94(m map[*int]*int, b bool) *int { // ERROR "leaking param: m to result ~r2 level=1"
+func foo94(m map[*int]*int, b bool) *int { // ERROR "leaking param: m to result ~r0 level=1"
 	for k, v := range m {
 		if b {
 			return k
@@ -799,12 +799,12 @@ func foo95(m map[*int]*int, x *int) { // ERROR "m does not escape$" "leaking par
 }
 
 // does not leak m but does leak content
-func foo96(m []*int) *int { // ERROR "leaking param: m to result ~r1 level=1"
+func foo96(m []*int) *int { // ERROR "leaking param: m to result ~r0 level=1"
 	return m[0]
 }
 
 // does leak m
-func foo97(m [1]*int) *int { // ERROR "leaking param: m to result ~r1 level=0$"
+func foo97(m [1]*int) *int { // ERROR "leaking param: m to result ~r0 level=0$"
 	return m[0]
 }
 
@@ -814,12 +814,12 @@ func foo98(m map[int]*int) *int { // ERROR "m does not escape$"
 }
 
 // does leak m
-func foo99(m *[1]*int) []*int { // ERROR "leaking param: m to result ~r1 level=0$"
+func foo99(m *[1]*int) []*int { // ERROR "leaking param: m to result ~r0 level=0$"
 	return m[:]
 }
 
 // does not leak m
-func foo100(m []*int) *int { // ERROR "leaking param: m to result ~r1 level=1"
+func foo100(m []*int) *int { // ERROR "leaking param: m to result ~r0 level=1"
 	for _, v := range m {
 		return v
 	}
@@ -827,7 +827,7 @@ func foo100(m []*int) *int { // ERROR "leaking param: m to result ~r1 level=1"
 }
 
 // does leak m
-func foo101(m [1]*int) *int { // ERROR "leaking param: m to result ~r1 level=0$"
+func foo101(m [1]*int) *int { // ERROR "leaking param: m to result ~r0 level=0$"
 	for _, v := range m {
 		return v
 	}
@@ -890,27 +890,27 @@ func foo110(x *int) *int { // ERROR "leaking param: x$"
 	return m[nil]
 }
 
-func foo111(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0"
+func foo111(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0"
 	m := []*int{x} // ERROR "\[\]\*int{...} does not escape$"
 	return m[0]
 }
 
-func foo112(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0$"
+func foo112(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0$"
 	m := [1]*int{x}
 	return m[0]
 }
 
-func foo113(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0$"
+func foo113(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0$"
 	m := Bar{ii: x}
 	return m.ii
 }
 
-func foo114(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0$"
+func foo114(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0$"
 	m := &Bar{ii: x} // ERROR "&Bar{...} does not escape$"
 	return m.ii
 }
 
-func foo115(x *int) *int { // ERROR "leaking param: x to result ~r1 level=0$"
+func foo115(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0$"
 	return (*int)(unsafe.Pointer(uintptr(unsafe.Pointer(x)) + 1))
 }
 
diff --git a/test/escape5.go b/test/escape5.go
index 82be2c38e7..73acfb46a9 100644
--- a/test/escape5.go
+++ b/test/escape5.go
@@ -22,19 +22,19 @@ func leaktoret(p *int) *int { // ERROR "leaking param: p to result"
 	return p
 }
 
-func leaktoret2(p *int) (*int, *int) { // ERROR "leaking param: p to result ~r1" "leaking param: p to result ~r2"
+func leaktoret2(p *int) (*int, *int) { // ERROR "leaking param: p to result ~r0" "leaking param: p to result ~r1"
 	return p, p
 }
 
-func leaktoret22(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r2" "leaking param: q to result ~r3"
+func leaktoret22(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r0" "leaking param: q to result ~r1"
 	return p, q
 }
 
-func leaktoret22b(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r3" "leaking param: q to result ~r2"
+func leaktoret22b(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r1" "leaking param: q to result ~r0"
 	return leaktoret22(q, p)
 }
 
-func leaktoret22c(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r3" "leaking param: q to result ~r2"
+func leaktoret22c(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r1" "leaking param: q to result ~r0"
 	r, s := leaktoret22(q, p)
 	return r, s
 }
diff --git a/test/escape_array.go b/test/escape_array.go
index 0d07fd861f..83062c9436 100644
--- a/test/escape_array.go
+++ b/test/escape_array.go
@@ -12,15 +12,15 @@ var Ssink *string
 
 type U [2]*string
 
-func bar(a, b *string) U { // ERROR "leaking param: a to result ~r2 level=0$" "leaking param: b to result ~r2 level=0$"
+func bar(a, b *string) U { // ERROR "leaking param: a to result ~r0 level=0$" "leaking param: b to result ~r0 level=0$"
 	return U{a, b}
 }
 
-func foo(x U) U { // ERROR "leaking param: x to result ~r1 level=0$"
+func foo(x U) U { // ERROR "leaking param: x to result ~r0 level=0$"
 	return U{x[1], x[0]}
 }
 
-func bff(a, b *string) U { // ERROR "leaking param: a to result ~r2 level=0$" "leaking param: b to result ~r2 level=0$"
+func bff(a, b *string) U { // ERROR "leaking param: a to result ~r0 level=0$" "leaking param: b to result ~r0 level=0$"
 	return foo(foo(bar(a, b)))
 }
 
@@ -41,27 +41,27 @@ func tbff2() *string {
 	return u[1]
 }
 
-func car(x U) *string { // ERROR "leaking param: x to result ~r1 level=0$"
+func car(x U) *string { // ERROR "leaking param: x to result ~r0 level=0$"
 	return x[0]
 }
 
 // BAD: need fine-grained analysis to track x[0] and x[1] differently.
-func fun(x U, y *string) *string { // ERROR "leaking param: x to result ~r2 level=0$" "leaking param: y to result ~r2 level=0$"
+func fun(x U, y *string) *string { // ERROR "leaking param: x to result ~r0 level=0$" "leaking param: y to result ~r0 level=0$"
 	x[0] = y
 	return x[1]
 }
 
-func fup(x *U, y *string) *string { // ERROR "leaking param: x to result ~r2 level=1$" "leaking param: y$"
+func fup(x *U, y *string) *string { // ERROR "leaking param: x to result ~r0 level=1$" "leaking param: y$"
 	x[0] = y // leaking y to heap is intended
 	return x[1]
 }
 
-func fum(x *U, y **string) *string { // ERROR "leaking param: x to result ~r2 level=1$" "leaking param content: y$"
+func fum(x *U, y **string) *string { // ERROR "leaking param: x to result ~r0 level=1$" "leaking param content: y$"
 	x[0] = *y
 	return x[1]
 }
 
-func fuo(x *U, y *U) *string { // ERROR "leaking param: x to result ~r2 level=1$" "leaking param content: y$"
+func fuo(x *U, y *U) *string { // ERROR "leaking param: x to result ~r0 level=1$" "leaking param content: y$"
 	x[0] = y[0]
 	return x[1]
 }
diff --git a/test/escape_calls.go b/test/escape_calls.go
index 9e1db5426e..aa7c7f516c 100644
--- a/test/escape_calls.go
+++ b/test/escape_calls.go
@@ -11,7 +11,7 @@
 
 package foo
 
-func f(buf []byte) []byte { // ERROR "leaking param: buf to result ~r1 level=0$"
+func f(buf []byte) []byte { // ERROR "leaking param: buf to result ~r0 level=0$"
 	return buf
 }
 
diff --git a/test/escape_closure.go b/test/escape_closure.go
index 9152319fe0..bd6c025476 100644
--- a/test/escape_closure.go
+++ b/test/escape_closure.go
@@ -44,7 +44,7 @@ func ClosureCallArgs3() {
 
 func ClosureCallArgs4() {
 	x := 0
-	_ = func(p *int) *int { // ERROR "leaking param: p to result ~r1" "func literal does not escape"
+	_ = func(p *int) *int { // ERROR "leaking param: p to result ~r0" "func literal does not escape"
 		return p
 	}(&x)
 }
@@ -111,7 +111,7 @@ func ClosureCallArgs11() {
 
 func ClosureCallArgs12() {
 	x := 0
-	defer func(p *int) *int { // ERROR "leaking param: p to result ~r1" "func literal does not escape"
+	defer func(p *int) *int { // ERROR "leaking param: p to result ~r0" "func literal does not escape"
 		return p
 	}(&x)
 }
@@ -126,7 +126,7 @@ func ClosureCallArgs13() {
 func ClosureCallArgs14() {
 	x := 0
 	p := &x
-	_ = func(p **int) *int { // ERROR "leaking param: p to result ~r1 level=1" "func literal does not escape"
+	_ = func(p **int) *int { // ERROR "leaking param: p to result ~r0 level=1" "func literal does not escape"
 		return *p
 	}(&p)
 }
@@ -145,7 +145,7 @@ func ClosureLeak1(s string) string { // ERROR "s does not escape"
 }
 
 // See #14409 -- returning part of captured var leaks it.
-func ClosureLeak1a(a ...string) string { // ERROR "leaking param: a to result ~r1 level=1$"
+func ClosureLeak1a(a ...string) string { // ERROR "leaking param: a to result ~r0 level=1$"
 	return func() string { // ERROR "func literal does not escape"
 		return a[0]
 	}()
diff --git a/test/escape_param.go b/test/escape_param.go
index dc93f689cf..b630bae88f 100644
--- a/test/escape_param.go
+++ b/test/escape_param.go
@@ -16,7 +16,7 @@ func zero() int { return 0 }
 var sink interface{}
 
 // in -> out
-func param0(p *int) *int { // ERROR "leaking param: p to result ~r1"
+func param0(p *int) *int { // ERROR "leaking param: p to result ~r0"
 	return p
 }
 
@@ -31,7 +31,7 @@ func caller0b() {
 }
 
 // in, in -> out, out
-func param1(p1, p2 *int) (*int, *int) { // ERROR "leaking param: p1 to result ~r2" "leaking param: p2 to result ~r3"
+func param1(p1, p2 *int) (*int, *int) { // ERROR "leaking param: p1 to result ~r0" "leaking param: p2 to result ~r1"
 	return p1, p2
 }
 
@@ -222,7 +222,7 @@ func caller8() {
 }
 
 // *in -> out
-func param9(p ***int) **int { // ERROR "leaking param: p to result ~r1 level=1"
+func param9(p ***int) **int { // ERROR "leaking param: p to result ~r0 level=1"
 	return *p
 }
 
@@ -241,7 +241,7 @@ func caller9b() {
 }
 
 // **in -> out
-func param10(p ***int) *int { // ERROR "leaking param: p to result ~r1 level=2"
+func param10(p ***int) *int { // ERROR "leaking param: p to result ~r0 level=2"
 	return **p
 }
 
@@ -436,6 +436,6 @@ func param14a(x [4]*int) interface{} { // ERROR "leaking param: x$"
 
 // Convert to a direct interface, does not need an allocation.
 // So x only leaks to result.
-func param14b(x *int) interface{} { // ERROR "leaking param: x to result ~r1 level=0"
+func param14b(x *int) interface{} { // ERROR "leaking param: x to result ~r0 level=0"
 	return x
 }
diff --git a/test/escape_runtime_atomic.go b/test/escape_runtime_atomic.go
index 62e8fede27..30d1d0c0c1 100644
--- a/test/escape_runtime_atomic.go
+++ b/test/escape_runtime_atomic.go
@@ -13,8 +13,8 @@ import (
 	"unsafe"
 )
 
-// BAD: should always be "leaking param: addr to result ~r1 level=1$".
-func Loadp(addr unsafe.Pointer) unsafe.Pointer { // ERROR "leaking param: addr( to result ~r1 level=1)?$"
+// BAD: should always be "leaking param: addr to result ~r0 level=1$".
+func Loadp(addr unsafe.Pointer) unsafe.Pointer { // ERROR "leaking param: addr( to result ~r0 level=1)?$"
 	return atomic.Loadp(addr)
 }
 
diff --git a/test/escape_slice.go b/test/escape_slice.go
index d60414736c..055b60be41 100644
--- a/test/escape_slice.go
+++ b/test/escape_slice.go
@@ -101,7 +101,7 @@ func slice11() {
 	_ = s
 }
 
-func slice12(x []int) *[1]int { // ERROR "leaking param: x to result ~r1 level=0$"
+func slice12(x []int) *[1]int { // ERROR "leaking param: x to result ~r0 level=0$"
 	return (*[1]int)(x)
 }
 
@@ -110,7 +110,7 @@ func envForDir(dir string) []string { // ERROR "dir does not escape"
 	return mergeEnvLists([]string{"PWD=" + dir}, env) // ERROR ".PWD=. \+ dir escapes to heap" "\[\]string{...} does not escape"
 }
 
-func mergeEnvLists(in, out []string) []string { // ERROR "leaking param content: in" "leaking param content: out" "leaking param: out to result ~r2 level=0"
+func mergeEnvLists(in, out []string) []string { // ERROR "leaking param content: in" "leaking param content: out" "leaking param: out to result ~r0 level=0"
 NextVar:
 	for _, inkv := range in {
 		k := strings.SplitAfterN(inkv, "=", 2)[0]
diff --git a/test/escape_struct_return.go b/test/escape_struct_return.go
index 222ef8bc22..a42ae1e8c9 100644
--- a/test/escape_struct_return.go
+++ b/test/escape_struct_return.go
@@ -15,11 +15,11 @@ type U struct {
 	_spp **string
 }
 
-func A(sp *string, spp **string) U { // ERROR "leaking param: sp to result ~r2 level=0$" "leaking param: spp to result ~r2 level=0$"
+func A(sp *string, spp **string) U { // ERROR "leaking param: sp to result ~r0 level=0$" "leaking param: spp to result ~r0 level=0$"
 	return U{sp, spp}
 }
 
-func B(spp **string) U { // ERROR "leaking param: spp to result ~r1 level=0$"
+func B(spp **string) U { // ERROR "leaking param: spp to result ~r0 level=0$"
 	return U{*spp, spp}
 }
 
diff --git a/test/escape_unsafe.go b/test/escape_unsafe.go
index b34beacccb..cec6674a14 100644
--- a/test/escape_unsafe.go
+++ b/test/escape_unsafe.go
@@ -15,7 +15,7 @@ import (
 
 // (1) Conversion of a *T1 to Pointer to *T2.
 
-func convert(p *float64) *uint64 { // ERROR "leaking param: p to result ~r1 level=0$"
+func convert(p *float64) *uint64 { // ERROR "leaking param: p to result ~r0 level=0$"
 	return (*uint64)(unsafe.Pointer(p))
 }
 
@@ -39,12 +39,12 @@ func arithMask() unsafe.Pointer {
 // (5) Conversion of the result of reflect.Value.Pointer or
 // reflect.Value.UnsafeAddr from uintptr to Pointer.
 
-// BAD: should be "leaking param: p to result ~r1 level=0$"
+// BAD: should be "leaking param: p to result ~r0 level=0$"
 func valuePointer(p *int) unsafe.Pointer { // ERROR "leaking param: p$"
 	return unsafe.Pointer(reflect.ValueOf(p).Pointer())
 }
 
-// BAD: should be "leaking param: p to result ~r1 level=0$"
+// BAD: should be "leaking param: p to result ~r0 level=0$"
 func valueUnsafeAddr(p *int) unsafe.Pointer { // ERROR "leaking param: p$"
 	return unsafe.Pointer(reflect.ValueOf(p).Elem().UnsafeAddr())
 }
@@ -52,11 +52,11 @@ func valueUnsafeAddr(p *int) unsafe.Pointer { // ERROR "leaking param: p$"
 // (6) Conversion of a reflect.SliceHeader or reflect.StringHeader
 // Data field to or from Pointer.
 
-func fromSliceData(s []int) unsafe.Pointer { // ERROR "leaking param: s to result ~r1 level=0$"
+func fromSliceData(s []int) unsafe.Pointer { // ERROR "leaking param: s to result ~r0 level=0$"
 	return unsafe.Pointer((*reflect.SliceHeader)(unsafe.Pointer(&s)).Data)
 }
 
-func fromStringData(s string) unsafe.Pointer { // ERROR "leaking param: s to result ~r1 level=0$"
+func fromStringData(s string) unsafe.Pointer { // ERROR "leaking param: s to result ~r0 level=0$"
 	return unsafe.Pointer((*reflect.StringHeader)(unsafe.Pointer(&s)).Data)
 }
 
diff --git a/test/fixedbugs/issue12006.go b/test/fixedbugs/issue12006.go
index 0a2ef8dad0..e878bc48e2 100644
--- a/test/fixedbugs/issue12006.go
+++ b/test/fixedbugs/issue12006.go
@@ -87,7 +87,7 @@ func TFooI() {
 	FooI(a, b, c) // ERROR "a escapes to heap" "b escapes to heap" "... argument does not escape"
 }
 
-func FooJ(args ...interface{}) *int32 { // ERROR "leaking param: args to result ~r1 level=1"
+func FooJ(args ...interface{}) *int32 { // ERROR "leaking param: args to result ~r0 level=1"
 	for i := 0; i < len(args); i++ {
 		switch x := args[i].(type) {
 		case nil:
@@ -123,7 +123,7 @@ type fakeSlice struct {
 	a *[4]interface{}
 }
 
-func FooK(args fakeSlice) *int32 { // ERROR "leaking param: args to result ~r1 level=1"
+func FooK(args fakeSlice) *int32 { // ERROR "leaking param: args to result ~r0 level=1"
 	for i := 0; i < args.l; i++ {
 		switch x := (*args.a)[i].(type) {
 		case nil:
@@ -148,7 +148,7 @@ func TFooK2() {
 	isink = FooK(fs)
 }
 
-func FooL(args []interface{}) *int32 { // ERROR "leaking param: args to result ~r1 level=1"
+func FooL(args []interface{}) *int32 { // ERROR "leaking param: args to result ~r0 level=1"
 	for i := 0; i < len(args); i++ {
 		switch x := args[i].(type) {
 		case nil:
diff --git a/test/fixedbugs/issue12588.go b/test/fixedbugs/issue12588.go
index 950ef36e20..dc8111198c 100644
--- a/test/fixedbugs/issue12588.go
+++ b/test/fixedbugs/issue12588.go
@@ -35,7 +35,7 @@ func g(a *A) int { // ERROR "a does not escape"
 	return 0
 }
 
-func h(a *B) *uint64 { // ERROR "leaking param: a to result ~r1 level=1"
+func h(a *B) *uint64 { // ERROR "leaking param: a to result ~r0 level=1"
 	for i, x := range &a.b {
 		if i == 0 {
 			return x
@@ -44,7 +44,7 @@ func h(a *B) *uint64 { // ERROR "leaking param: a to result ~r1 level=1"
 	return nil
 }
 
-func h2(a *B) *uint64 { // ERROR "leaking param: a to result ~r1 level=1"
+func h2(a *B) *uint64 { // ERROR "leaking param: a to result ~r0 level=1"
 	p := &a.b
 	for i, x := range p {
 		if i == 0 {
@@ -55,7 +55,7 @@ func h2(a *B) *uint64 { // ERROR "leaking param: a to result ~r1 level=1"
 }
 
 // Seems like below should be level=1, not 0.
-func k(a B) *uint64 { // ERROR "leaking param: a to result ~r1 level=0"
+func k(a B) *uint64 { // ERROR "leaking param: a to result ~r0 level=0"
 	for i, x := range &a.b {
 		if i == 0 {
 			return x
diff --git a/test/fixedbugs/issue42284.dir/a.go b/test/fixedbugs/issue42284.dir/a.go
index ffe9310be3..f7fd80bd20 100644
--- a/test/fixedbugs/issue42284.dir/a.go
+++ b/test/fixedbugs/issue42284.dir/a.go
@@ -13,7 +13,7 @@ func E() I { // ERROR "can inline E"
 	return T(0) // ERROR "T\(0\) escapes to heap"
 }
 
-func F(i I) I { // ERROR "can inline F" "leaking param: i to result ~r1 level=0"
+func F(i I) I { // ERROR "can inline F" "leaking param: i to result ~r0 level=0"
 	i = nil
 	return i
 }