cmd/gofmt: handle ... in rewrite of calls

Fixes issue 5059.

R=golang-dev, r
CC=golang-dev
https://codereview.appspot.com/8284043

6 files changed, 73 insertions, 1 deletions

diff --git a/src/cmd/gofmt/gofmt_test.go b/src/cmd/gofmt/gofmt_test.go
index 202d0a50c..8ff00a253 100644
--- a/src/cmd/gofmt/gofmt_test.go
+++ b/src/cmd/gofmt/gofmt_test.go
@@ -82,6 +82,8 @@ var tests = []struct {
 	{"testdata/rewrite3.input", "-r=x->x"},
 	{"testdata/rewrite4.input", "-r=(x)->x"},
 	{"testdata/rewrite5.input", "-r=x+x->2*x"},
+	{"testdata/rewrite6.input", "-r=fun(x)->Fun(x)"},
+	{"testdata/rewrite7.input", "-r=fun(x...)->Fun(x)"},
 	{"testdata/stdin*.input", "-stdin"},
 	{"testdata/comments.input", ""},
 	{"testdata/import.input", ""},
diff --git a/src/cmd/gofmt/rewrite.go b/src/cmd/gofmt/rewrite.go
index dfabb6198..1aa1f6ed0 100644
--- a/src/cmd/gofmt/rewrite.go
+++ b/src/cmd/gofmt/rewrite.go
@@ -107,6 +107,7 @@ var (
 	identType     = reflect.TypeOf((*ast.Ident)(nil))
 	objectPtrType = reflect.TypeOf((*ast.Object)(nil))
 	positionType  = reflect.TypeOf(token.NoPos)
+	callExprType  = reflect.TypeOf((*ast.CallExpr)(nil))
 	scopePtrType  = reflect.TypeOf((*ast.Scope)(nil))
 )
 
@@ -192,8 +193,17 @@ func match(m map[string]reflect.Value, pattern, val reflect.Value) bool {
 		v := val.Interface().(*ast.Ident)
 		return p == nil && v == nil || p != nil && v != nil && p.Name == v.Name
 	case objectPtrType, positionType:
-		// object pointers and token positions don't need to match
+		// object pointers and token positions always match
 		return true
+	case callExprType:
+		// For calls, the Ellipsis fields (token.Position) must
+		// match since that is how f(x) and f(x...) are different.
+		// Check them here but fall through for the remaining fields.
+		p := pattern.Interface().(*ast.CallExpr)
+		v := val.Interface().(*ast.CallExpr)
+		if p.Ellipsis.IsValid() != v.Ellipsis.IsValid() {
+			return false
+		}
 	}
 
 	p := reflect.Indirect(pattern)
diff --git a/src/cmd/gofmt/testdata/rewrite6.golden b/src/cmd/gofmt/testdata/rewrite6.golden
new file mode 100644
index 000000000..e565dbdd9
--- /dev/null
+++ b/src/cmd/gofmt/testdata/rewrite6.golden
@@ -0,0 +1,15 @@
+// Copyright 2013 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.
+
+// Rewriting of calls must take the ... (ellipsis)
+// attribute for the last argument into account.
+
+package p
+
+func fun(x []int) {}
+
+func g(x []int) {
+	Fun(x)    // -r='fun(x)->Fun(x)' should rewrite this to Fun(x)
+	fun(x...) // -r='fun(x)->Fun(x)' should not rewrite this
+}
diff --git a/src/cmd/gofmt/testdata/rewrite6.input b/src/cmd/gofmt/testdata/rewrite6.input
new file mode 100644
index 000000000..8c088b3e8
--- /dev/null
+++ b/src/cmd/gofmt/testdata/rewrite6.input
@@ -0,0 +1,15 @@
+// Copyright 2013 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.
+
+// Rewriting of calls must take the ... (ellipsis)
+// attribute for the last argument into account.
+
+package p
+
+func fun(x []int) {}
+
+func g(x []int) {
+	fun(x)    // -r='fun(x)->Fun(x)' should rewrite this to Fun(x)
+	fun(x...) // -r='fun(x)->Fun(x)' should not rewrite this
+}
diff --git a/src/cmd/gofmt/testdata/rewrite7.golden b/src/cmd/gofmt/testdata/rewrite7.golden
new file mode 100644
index 000000000..29babad9f
--- /dev/null
+++ b/src/cmd/gofmt/testdata/rewrite7.golden
@@ -0,0 +1,15 @@
+// Copyright 2013 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.
+
+// Rewriting of calls must take the ... (ellipsis)
+// attribute for the last argument into account.
+
+package p
+
+func fun(x []int) {}
+
+func g(x []int) {
+	fun(x) // -r='fun(x...)->Fun(x)' should not rewrite this
+	Fun(x) // -r='fun(x...)->Fun(x)' should rewrite this to Fun(x)
+}
diff --git a/src/cmd/gofmt/testdata/rewrite7.input b/src/cmd/gofmt/testdata/rewrite7.input
new file mode 100644
index 000000000..073e2a3e6
--- /dev/null
+++ b/src/cmd/gofmt/testdata/rewrite7.input
@@ -0,0 +1,15 @@
+// Copyright 2013 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.
+
+// Rewriting of calls must take the ... (ellipsis)
+// attribute for the last argument into account.
+
+package p
+
+func fun(x []int) {}
+
+func g(x []int) {
+	fun(x)    // -r='fun(x...)->Fun(x)' should not rewrite this
+	fun(x...) // -r='fun(x...)->Fun(x)' should rewrite this to Fun(x)
+}