cmd/compile: report error for unexported name only once

Fixes #22921

Change-Id: If29bd962335ac7676ea4f379727db3d55ae1bf8e
Reviewed-on: https://go-review.googlesource.com/c/go/+/250177
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

diff --git a/src/cmd/compile/internal/gc/dcl.go b/src/cmd/compile/internal/gc/dcl.go
index cd64d9a7bff940611126ea11a148cb21ce58a86c..4f6fddd08975572962790d618d64062fdf23f6f2 100644 (file)
--- a/src/cmd/compile/internal/gc/dcl.go
+++ b/src/cmd/compile/internal/gc/dcl.go
@@ -297,6 +297,16 @@ func oldname(s *types.Sym) *Node {
        return n
 }
 
+// importName is like oldname, but it reports an error if sym is from another package and not exported.
+func importName(sym *types.Sym) *Node {
+       n := oldname(sym)
+       if !types.IsExported(sym.Name) && sym.Pkg != localpkg {
+               n.SetDiag(true)
+               yyerror("cannot refer to unexported name %s.%s", sym.Pkg.Name, sym.Name)
+       }
+       return n
+}
+
 // := declarations
 func colasname(n *Node) bool {
        switch n.Op {

diff --git a/src/cmd/compile/internal/gc/noder.go b/src/cmd/compile/internal/gc/noder.go
index 802aab226847d56ebb389cfa7eb49a6b47fbc057..590c1a16de9a448ff59b9c04c1153f990bba6aca 100644 (file)
--- a/src/cmd/compile/internal/gc/noder.go
+++ b/src/cmd/compile/internal/gc/noder.go
@@ -653,7 +653,7 @@ func (p *noder) expr(expr syntax.Expr) *Node {
                obj := p.expr(expr.X)
                if obj.Op == OPACK {
                        obj.Name.SetUsed(true)
-                       return oldname(restrictlookup(expr.Sel.Value, obj.Name.Pkg))
+                       return importName(obj.Name.Pkg.Lookup(expr.Sel.Value))
                }
                n := nodSym(OXDOT, obj, p.name(expr.Sel))
                n.Pos = p.pos(expr) // lineno may have been changed by p.expr(expr.X)
@@ -857,7 +857,7 @@ func (p *noder) interfaceType(expr *syntax.InterfaceType) *Node {
                p.setlineno(method)
                var n *Node
                if method.Name == nil {
-                       n = p.nodSym(method, ODCLFIELD, oldname(p.packname(method.Type)), nil)
+                       n = p.nodSym(method, ODCLFIELD, importName(p.packname(method.Type)), nil)
                } else {
                        mname := p.name(method.Name)
                        sig := p.typeExpr(method.Type)
@@ -896,7 +896,7 @@ func (p *noder) packname(expr syntax.Expr) *types.Sym {
                        def.Name.SetUsed(true)
                        pkg = def.Name.Pkg
                }
-               return restrictlookup(expr.Sel.Value, pkg)
+               return pkg.Lookup(expr.Sel.Value)
        }
        panic(fmt.Sprintf("unexpected packname: %#v", expr))
 }
@@ -911,7 +911,7 @@ func (p *noder) embedded(typ syntax.Expr) *Node {
        }
 
        sym := p.packname(typ)
-       n := p.nodSym(typ, ODCLFIELD, oldname(sym), lookup(sym.Name))
+       n := p.nodSym(typ, ODCLFIELD, importName(sym), lookup(sym.Name))
        n.SetEmbedded(true)
 
        if isStar {

diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index 9362c7428865a6f7d10b1e75fb8071d799c462d7..9c6cd24eb78b88b64a8a0a84b53782c285e85fe4 100644 (file)
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -271,13 +271,6 @@ func autolabel(prefix string) *types.Sym {
        return lookupN(prefix, int(n))
 }
 
-func restrictlookup(name string, pkg *types.Pkg) *types.Sym {
-       if !types.IsExported(name) && pkg != localpkg {
-               yyerror("cannot refer to unexported name %s.%s", pkg.Name, name)
-       }
-       return pkg.Lookup(name)
-}
-
 // find all the exported symbols in package opkg
 // and make them available in the current package
 func importdot(opkg *types.Pkg, pack *Node) {

diff --git a/test/fixedbugs/bug229.go b/test/fixedbugs/bug229.go
index 4baf65e48b758d61eab2d7dfee030ebb5ff141ed..a30202fa2c75cd81542d67756981c8416087e80d 100644 (file)
--- a/test/fixedbugs/bug229.go
+++ b/test/fixedbugs/bug229.go
@@ -10,11 +10,11 @@ import "testing"
 
 func main() {
        var t testing.T
-       
+
        // make sure error mentions that
        // name is unexported, not just "name not found".
 
-       t.common.name = nil     // ERROR "unexported"
-       
-       println(testing.anyLowercaseName("asdf"))       // ERROR "unexported" "undefined: testing.anyLowercaseName"
+       t.common.name = nil // ERROR "unexported"
+
+       println(testing.anyLowercaseName("asdf")) // ERROR "unexported"
 }

diff --git a/test/fixedbugs/issue22921.go b/test/fixedbugs/issue22921.go
new file mode 100644 (file)
index 0000000..04f78b2
--- /dev/null
+++ b/test/fixedbugs/issue22921.go
@@ -0,0 +1,18 @@
+// errorcheck
+
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import "bytes"
+
+type _ struct{ bytes.nonexist } // ERROR "unexported"
+
+type _ interface{ bytes.nonexist } // ERROR "unexported"
+
+func main() {
+       var _ bytes.Buffer
+       var _ bytes.buffer // ERROR "unexported"
+}

diff --git a/test/runtime.go b/test/runtime.go
index 0cf781b814bdad5711681d671520dc70fb81b8de..bccc9b53afc021950284370cc95834b9aae147d2 100644 (file)
--- a/test/runtime.go
+++ b/test/runtime.go
@@ -17,5 +17,5 @@ package main
 import "runtime"
 
 func main() {
-       runtime.printbool(true) // ERROR "unexported" "undefined"
+       runtime.printbool(true) // ERROR "unexported"
 }