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author | Josh Bleecher Snyder <josharian@gmail.com> | 2016-05-30 16:42:38 -0700 |
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committer | Josh Bleecher Snyder <josharian@gmail.com> | 2016-05-31 20:31:00 +0000 |
commit | 0e13dbc1a91cbe00e3c83a55f56db69380fe8f68 (patch) | |
tree | 5d21e5be585c78c83ce8fa2f28aae8246293c198 | |
parent | 7cd6cae6a63f09caa88bbcc394053b40cdeeccd1 (diff) | |
download | go-0e13dbc1a91cbe00e3c83a55f56db69380fe8f68.tar.gz go-0e13dbc1a91cbe00e3c83a55f56db69380fe8f68.zip |
cmd/compile: disallow multiple nil cases in a type switch
Fixes #15898.
Change-Id: I66e2ad21f283563c7142aa820f0354711d964768
Reviewed-on: https://go-review.googlesource.com/23573
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
-rw-r--r-- | src/cmd/compile/internal/gc/swt.go | 8 | ||||
-rw-r--r-- | test/fixedbugs/issue15898.go | 18 |
2 files changed, 25 insertions, 1 deletions
diff --git a/src/cmd/compile/internal/gc/swt.go b/src/cmd/compile/internal/gc/swt.go index aac92fd311..4940c97a90 100644 --- a/src/cmd/compile/internal/gc/swt.go +++ b/src/cmd/compile/internal/gc/swt.go @@ -104,7 +104,7 @@ func typecheckswitch(n *Node) { n.Type = t - var def *Node + var def, niltype *Node for _, ncase := range n.List.Slice() { setlineno(n) if ncase.List.Len() == 0 { @@ -150,6 +150,12 @@ func typecheckswitch(n *Node) { var ptr int switch { case n1.Op == OLITERAL && n1.Type.IsKind(TNIL): + // case nil: + if niltype != nil { + Yyerror("multiple nil cases in type switch (first at %v)", niltype.Line()) + } else { + niltype = ncase + } case n1.Op != OTYPE && n1.Type != nil: // should this be ||? Yyerror("%v is not a type", Nconv(n1, FmtLong)) // reset to original type diff --git a/test/fixedbugs/issue15898.go b/test/fixedbugs/issue15898.go new file mode 100644 index 0000000000..7b66ea23dc --- /dev/null +++ b/test/fixedbugs/issue15898.go @@ -0,0 +1,18 @@ +// errorcheck + +// Copyright 2016 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 p + +func f(e interface{}) { + switch e.(type) { + case nil, nil: // ERROR "multiple nil cases in type switch" + } + + switch e.(type) { + case nil: + case nil: // ERROR "multiple nil cases in type switch" + } +} |