cmd/compile: allow fieldtrack of unexported fields

The fieldtrack support is experimental and used mainly inside Google,
where we have included this change for years. No reason not to make
it in the public copy.

Change-Id: I5233e4e775ccce60a17098c007aed8c82a0425d7
Reviewed-on: https://go-review.googlesource.com/c/go/+/387355
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/cmd/compile/internal/walk/expr.go b/src/cmd/compile/internal/walk/expr.go
index e5bf6cf0b5e3670a8df0c827f1385ff40251f54d..43201dbd3d4e0dad3bc3ca05e66c933666439f79 100644 (file)
--- a/src/cmd/compile/internal/walk/expr.go
+++ b/src/cmd/compile/internal/walk/expr.go
@@ -1012,9 +1012,6 @@ func usefield(n *ir.SelectorExpr) {
        if outer.Sym() == nil {
                base.Errorf("tracked field must be in named struct type")
        }
-       if !types.IsExported(field.Sym.Name) {
-               base.Errorf("tracked field must be exported (upper case)")
-       }
 
        sym := reflectdata.TrackSym(outer, field)
        if ir.CurFunc.FieldTrack == nil {