1 files changed, 139 insertions, 0 deletions
diff --git a/src/go/ast/issues_test.go b/src/go/ast/issues_test.go
new file mode 100644
index 0000000..28d6a30
--- /dev/null
+++ b/src/go/ast/issues_test.go
@@ -0,0 +1,139 @@
+// Copyright 2019 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 ast_test
+
+import (
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"testing"
+)
+
+func TestIssue33649(t *testing.T) {
+	for _, src := range []string{
+		`package p; func _()`,
+		`package p; func _() {`,
+		`package p; func _() { _ = 0`,
+		`package p; func _() { _ = 0 }`,
+	} {
+		fset := token.NewFileSet()
+		f, _ := parser.ParseFile(fset, "", src, parser.AllErrors)
+		if f == nil {
+			panic("invalid test setup: parser didn't return an AST")
+		}
+
+		// find corresponding token.File
+		var tf *token.File
+		fset.Iterate(func(f *token.File) bool {
+			tf = f
+			return true
+		})
+		tfEnd := tf.Base() + tf.Size()
+
+		fd := f.Decls[len(f.Decls)-1].(*ast.FuncDecl)
+		fdEnd := int(fd.End())
+
+		if fdEnd != tfEnd {
+			t.Errorf("%q: got fdEnd = %d; want %d (base = %d, size = %d)", src, fdEnd, tfEnd, tf.Base(), tf.Size())
+		}
+	}
+}
+
+// TestIssue28089 exercises the IsGenerated function.
+func TestIssue28089(t *testing.T) {
+	for i, test := range []struct {
+		src  string
+		want bool
+	}{
+		// No file comments.
+		{`package p`, false},
+		// Irrelevant file comments.
+		{`// Package p doc.
+package p`, false},
+		// Special comment misplaced after package decl.
+		{`// Package p doc.
+package p
+// Code generated by gen. DO NOT EDIT.
+`, false},
+		// Special comment appears inside string literal.
+		{`// Package p doc.
+package p
+const c = "` + "`" + `
+// Code generated by gen. DO NOT EDIT.
+` + "`" + `
+`, false},
+		// Special comment appears properly.
+		{`// Copyright 2019 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 doc comment goes here.
+//
+// Code generated by gen. DO NOT EDIT.
+package p
+
+... `, true},
+		// Special comment is indented.
+		//
+		// Strictly, the indent should cause IsGenerated to
+		// yield false, but we cannot detect the indent
+		// without either source text or a token.File.
+		// In other words, the function signature cannot
+		// implement the spec. Let's brush this under the
+		// rug since well-formatted code has no indent.
+		{`// Package p doc comment goes here.
+//
+	// Code generated by gen. DO NOT EDIT.
+package p
+
+... `, true},
+		// Special comment has unwanted spaces after "DO NOT EDIT."
+		{`// Copyright 2019 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 doc comment goes here.
+//
+// Code generated by gen. DO NOT EDIT. 
+package p
+
+... `, false},
+		// Special comment has rogue interior space.
+		{`//     Code generated by gen. DO NOT EDIT.
+package p
+`, false},
+		// Special comment lacks the middle portion.
+		{`// Code generated DO NOT EDIT.
+package p
+`, false},
+		// Special comment (incl. "//") appears within a /* block */ comment,
+		// an obscure corner case of the spec.
+		{`/* start of a general comment
+
+// Code generated by tool; DO NOT EDIT.
+
+end of a general comment */
+
+// +build !dev
+
+// Package comment.
+package p
+
+// Does match even though it's inside general comment (/*-style).
+`, true},
+	} {
+		fset := token.NewFileSet()
+		f, err := parser.ParseFile(fset, "", test.src, parser.PackageClauseOnly|parser.ParseComments)
+		if f == nil {
+			t.Fatalf("parse %d failed to return AST: %v", i, err)
+		}
+
+		got := ast.IsGenerated(f)
+		if got != test.want {
+			t.Errorf("%d: IsGenerated on <<%s>> returned %t", i, test.src, got)
+		}
+	}
+
+}