From 7f3313133ee3e40515aa99d3618b8e5eafed42d6 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20Mart=C3=AD?= Date: Sun, 7 Oct 2018 12:45:56 +0100 Subject: [PATCH] cmd/compile: don't panic on invalid map key declarations MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In golang.org/cl/75310, the compiler's typechecker was changed so that map key types were validated at a later stage, to make sure that all the necessary type information was present. This still worked for map type declarations, but caused a regression for top-level map variable declarations. These now caused a fatal panic instead of a typechecking error. The cause was that checkMapKeys was run too early, before all typechecking was done. In particular, top-level map variable declarations are typechecked as external declarations, much later than where checkMapKeys was run. Add a test case for both exported and unexported top-level map declarations, and add a second call to checkMapKeys at the actual end of typechecking. Simply moving the one call isn't a good solution either; the comments expand on that. Fixes #28058. Change-Id: Ia5febb01a1d877447cf66ba44fb49a7e0f4f18a5 Reviewed-on: https://go-review.googlesource.com/c/140417 Run-TryBot: Daniel Martí TryBot-Result: Gobot Gobot Reviewed-by: Robert Griesemer --- src/cmd/compile/internal/gc/main.go | 7 ++++++- test/fixedbugs/issue28058.go | 13 +++++++++++++ 2 files changed, 19 insertions(+), 1 deletion(-) create mode 100644 test/fixedbugs/issue28058.go diff --git a/src/cmd/compile/internal/gc/main.go b/src/cmd/compile/internal/gc/main.go index 02aec32685..9a226318b9 100644 --- a/src/cmd/compile/internal/gc/main.go +++ b/src/cmd/compile/internal/gc/main.go @@ -534,7 +534,9 @@ func Main(archInit func(*Arch)) { fcount++ } } - // With all types ckecked, it's now safe to verify map keys. + // With all types ckecked, it's now safe to verify map keys. One single + // check past phase 9 isn't sufficient, as we may exit with other errors + // before then, thus skipping map key errors. checkMapKeys() timings.AddEvent(fcount, "funcs") @@ -678,6 +680,9 @@ func Main(archInit func(*Arch)) { externdcl[i] = typecheck(externdcl[i], Erv) } } + // Check the map keys again, since we typechecked the external + // declarations. + checkMapKeys() if nerrors+nsavederrors != 0 { errorexit() diff --git a/test/fixedbugs/issue28058.go b/test/fixedbugs/issue28058.go new file mode 100644 index 0000000000..d8206e7357 --- /dev/null +++ b/test/fixedbugs/issue28058.go @@ -0,0 +1,13 @@ +// 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. + +// Issue 14988: declaring a map with an invalid key type should not cause a +// fatal panic. + +package main + +var x map[func()]int // ERROR "invalid map key type" +var X map[func()]int // ERROR "invalid map key type"