From ba6974fdc3ce96acc259055a051bbfcbabce2be4 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Daniel=20Mart=C3=AD?= Date: Tue, 17 Jul 2018 14:38:52 +0100 Subject: [PATCH] cmd/compile: fix crash on invalid struct literal MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit If one tries to use promoted fields in a struct literal, the compiler errors correctly. However, if the embedded fields are of struct pointer type, the field.Type.Sym.Name expression below panics. This is because field.Type.Sym is nil in that case. We can simply use field.Sym.Name in this piece of code though, as it only concerns embedded fields, in which case what we are after is the field name. Added a test mirroring fixedbugs/issue23609.go, but with pointer types. Fixes #26416. Change-Id: Ia46ce62995c9e1653f315accb99d592aff2f285e Reviewed-on: https://go-review.googlesource.com/124395 Run-TryBot: Daniel Martí TryBot-Result: Gobot Gobot Reviewed-by: Emmanuel Odeke Reviewed-by: Matthew Dempsky --- src/cmd/compile/internal/gc/typecheck.go | 2 +- test/fixedbugs/issue26416.go | 27 ++++++++++++++++++++++++ 2 files changed, 28 insertions(+), 1 deletion(-) create mode 100644 test/fixedbugs/issue26416.go diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go index 1b68e057fc..51dd0dba87 100644 --- a/src/cmd/compile/internal/gc/typecheck.go +++ b/src/cmd/compile/internal/gc/typecheck.go @@ -3152,7 +3152,7 @@ func typecheckcomplit(n *Node) *Node { // dotpath returns the parent embedded types in reverse order. var ep []string for ei := len(p) - 1; ei >= 0; ei-- { - ep = append(ep, p[ei].field.Type.Sym.Name) + ep = append(ep, p[ei].field.Sym.Name) } ep = append(ep, l.Sym.Name) yyerror("cannot use promoted field %v in struct literal of type %v", strings.Join(ep, "."), t) diff --git a/test/fixedbugs/issue26416.go b/test/fixedbugs/issue26416.go new file mode 100644 index 0000000000..bc37fd9d3a --- /dev/null +++ b/test/fixedbugs/issue26416.go @@ -0,0 +1,27 @@ +// errorcheck + +// Copyright 2018 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 + +type t1 struct { + t1f1 int + t1f2 int +} +type t2 struct { + t2f1 int + t2f2 int + *t1 +} +type t3 struct { + t3f1 int + *t2 +} + +var ( + _ = t2{t1f1: 600} // ERROR "cannot use promoted field t1.t1f1 in struct literal of type t2" + _ = t3{t1f2: 800} // ERROR "cannot use promoted field t2.t1.t1f2 in struct literal of type t3" + _ = t3{t2f1: 900} // ERROR "cannot use promoted field t2.t2f1 in struct literal of type t3" +) -- 2.48.1