[release-branch.go1.15] cmd/compile: make go:notinheap error message friendlier for cgo

Update #40954

Change-Id: Ifaab7349631ccb12fc892882bbdf7f0ebf3d845f
Reviewed-on: https://go-review.googlesource.com/c/go/+/251158
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Keith Randall <khr@golang.org>
Reviewed-on: https://go-review.googlesource.com/c/go/+/255338
Reviewed-by: Austin Clements <austin@google.com>

4 files changed, 10 insertions, 10 deletions

diff --git a/src/cmd/compile/internal/gc/escape.go b/src/cmd/compile/internal/gc/escape.go
index d5cca4a38b..08000dd374 100644
--- a/src/cmd/compile/internal/gc/escape.go
+++ b/src/cmd/compile/internal/gc/escape.go
@@ -1030,7 +1030,7 @@ func (e *Escape) newLoc(n *Node, transient bool) *EscLocation {
 		Fatalf("e.curfn isn't set")
 	}
 	if n != nil && n.Type != nil && n.Type.NotInHeap() {
-		yyerrorl(n.Pos, "%v is go:notinheap; stack allocation disallowed", n.Type)
+		yyerrorl(n.Pos, "%v is incomplete (or unallocatable); stack allocation disallowed", n.Type)
 	}
 
 	n = canonicalNode(n)
diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index 9362c74288..c82eefb63d 100644
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -696,14 +696,14 @@ func convertop(srcConstant bool, src, dst *types.Type, why *string) Op {
 	// (a) Disallow (*T) to (*U) where T is go:notinheap but U isn't.
 	if src.IsPtr() && dst.IsPtr() && dst.Elem().NotInHeap() && !src.Elem().NotInHeap() {
 		if why != nil {
-			*why = fmt.Sprintf(":\n\t%v is go:notinheap, but %v is not", dst.Elem(), src.Elem())
+			*why = fmt.Sprintf(":\n\t%v is incomplete (or unallocatable), but %v is not", dst.Elem(), src.Elem())
 		}
 		return OXXX
 	}
 	// (b) Disallow string to []T where T is go:notinheap.
 	if src.IsString() && dst.IsSlice() && dst.Elem().NotInHeap() && (dst.Elem().Etype == types.Bytetype.Etype || dst.Elem().Etype == types.Runetype.Etype) {
 		if why != nil {
-			*why = fmt.Sprintf(":\n\t%v is go:notinheap", dst.Elem())
+			*why = fmt.Sprintf(":\n\t%v is incomplete (or unallocatable)", dst.Elem())
 		}
 		return OXXX
 	}
diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index b29f5ef5ec..56a03f1931 100644
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -471,10 +471,10 @@ func typecheck1(n *Node, top int) (res *Node) {
 			return n
 		}
 		if l.Type.NotInHeap() {
-			yyerror("go:notinheap map key not allowed")
+			yyerror("incomplete (or unallocatable) map key not allowed")
 		}
 		if r.Type.NotInHeap() {
-			yyerror("go:notinheap map value not allowed")
+			yyerror("incomplete (or unallocatable) map value not allowed")
 		}
 
 		setTypeNode(n, types.NewMap(l.Type, r.Type))
@@ -491,7 +491,7 @@ func typecheck1(n *Node, top int) (res *Node) {
 			return n
 		}
 		if l.Type.NotInHeap() {
-			yyerror("chan of go:notinheap type not allowed")
+			yyerror("chan of incomplete (or unallocatable) type not allowed")
 		}
 
 		setTypeNode(n, types.NewChan(l.Type, n.TChanDir()))
diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go
index 8dd1277705..af6602f70c 100644
--- a/src/cmd/compile/internal/gc/walk.go
+++ b/src/cmd/compile/internal/gc/walk.go
@@ -640,7 +640,7 @@ opswitch:
 			// x = append(...)
 			r := n.Right
 			if r.Type.Elem().NotInHeap() {
-				yyerror("%v is go:notinheap; heap allocation disallowed", r.Type.Elem())
+				yyerror("%v can't be allocated in Go; it is incomplete (or unallocatable)", r.Type.Elem())
 			}
 			switch {
 			case isAppendOfMake(r):
@@ -1152,7 +1152,7 @@ opswitch:
 
 	case ONEW:
 		if n.Type.Elem().NotInHeap() {
-			yyerror("%v is go:notinheap; heap allocation disallowed", n.Type.Elem())
+			yyerror("%v can't be allocated in Go; it is incomplete (or unallocatable)", n.Type.Elem())
 		}
 		if n.Esc == EscNone {
 			if n.Type.Elem().Width >= maxImplicitStackVarSize {
@@ -1323,7 +1323,7 @@ opswitch:
 		}
 		t := n.Type
 		if t.Elem().NotInHeap() {
-			yyerror("%v is go:notinheap; heap allocation disallowed", t.Elem())
+			yyerror("%v can't be allocated in Go; it is incomplete (or unallocatable)", t.Elem())
 		}
 		if n.Esc == EscNone {
 			if !isSmallMakeSlice(n) {
@@ -1400,7 +1400,7 @@ opswitch:
 
 		t := n.Type
 		if t.Elem().NotInHeap() {
-			yyerror("%v is go:notinheap; heap allocation disallowed", t.Elem())
+			yyerror("%v can't be allocated in Go; it is incomplete (or unallocatable)", t.Elem())
 		}
 
 		length := conv(n.Left, types.Types[TINT])