From 50fed64dd90ca6a58cfe8fa7c1061aa8666cc76f Mon Sep 17 00:00:00 2001
From: Keegan Carruthers-Smith <keegan.csmith@gmail.com>
Date: Fri, 4 Nov 2016 09:31:35 +0200
Subject: [PATCH] go/doc: don't panic if method is missing recv type

Fixes #17788

Change-Id: I2f8a11321dc8f10bebbc8df90ba00ec65b9ee0fa
Reviewed-on: https://go-review.googlesource.com/32790
Reviewed-by: Russ Cox <rsc@golang.org>
---
 src/go/doc/reader.go                    | 5 +++++
 src/go/doc/testdata/issue17788.0.golden | 8 ++++++++
 src/go/doc/testdata/issue17788.1.golden | 8 ++++++++
 src/go/doc/testdata/issue17788.2.golden | 8 ++++++++
 src/go/doc/testdata/issue17788.go       | 8 ++++++++
 5 files changed, 37 insertions(+)
 create mode 100644 src/go/doc/testdata/issue17788.0.golden
 create mode 100644 src/go/doc/testdata/issue17788.1.golden
 create mode 100644 src/go/doc/testdata/issue17788.2.golden
 create mode 100644 src/go/doc/testdata/issue17788.go

diff --git a/src/go/doc/reader.go b/src/go/doc/reader.go
index ca46a047d6a..8e823538689 100644
--- a/src/go/doc/reader.go
+++ b/src/go/doc/reader.go
@@ -362,6 +362,11 @@ func (r *reader) readFunc(fun *ast.FuncDecl) {
 	// associate methods with the receiver type, if any
 	if fun.Recv != nil {
 		// method
+		if len(fun.Recv.List) == 0 {
+			// should not happen (incorrect AST); (See issue 17788)
+			// don't show this method
+			return
+		}
 		recvTypeName, imp := baseTypeName(fun.Recv.List[0].Type)
 		if imp {
 			// should not happen (incorrect AST);
diff --git a/src/go/doc/testdata/issue17788.0.golden b/src/go/doc/testdata/issue17788.0.golden
new file mode 100644
index 00000000000..42c00da5041
--- /dev/null
+++ b/src/go/doc/testdata/issue17788.0.golden
@@ -0,0 +1,8 @@
+// 
+PACKAGE issue17788
+
+IMPORTPATH
+	testdata/issue17788
+
+FILENAMES
+	testdata/issue17788.go
diff --git a/src/go/doc/testdata/issue17788.1.golden b/src/go/doc/testdata/issue17788.1.golden
new file mode 100644
index 00000000000..42c00da5041
--- /dev/null
+++ b/src/go/doc/testdata/issue17788.1.golden
@@ -0,0 +1,8 @@
+// 
+PACKAGE issue17788
+
+IMPORTPATH
+	testdata/issue17788
+
+FILENAMES
+	testdata/issue17788.go
diff --git a/src/go/doc/testdata/issue17788.2.golden b/src/go/doc/testdata/issue17788.2.golden
new file mode 100644
index 00000000000..42c00da5041
--- /dev/null
+++ b/src/go/doc/testdata/issue17788.2.golden
@@ -0,0 +1,8 @@
+// 
+PACKAGE issue17788
+
+IMPORTPATH
+	testdata/issue17788
+
+FILENAMES
+	testdata/issue17788.go
diff --git a/src/go/doc/testdata/issue17788.go b/src/go/doc/testdata/issue17788.go
new file mode 100644
index 00000000000..883ad5f7695
--- /dev/null
+++ b/src/go/doc/testdata/issue17788.go
@@ -0,0 +1,8 @@
+// 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 issue17788
+
+func ( /* receiver type */ ) f0() {
+}