gofmt: rewriter matches apply to expressions only

Fixes #1384.

R=rsc
CC=golang-dev
https://golang.org/cl/3912041

diff --git a/src/cmd/gofmt/rewrite.go b/src/cmd/gofmt/rewrite.go
index 7fa8c909a9d4bfe8772adf5484adb68be144bd34..a87dbeb8cda1adcd51fcabfb345bf8c64e9558e0 100644 (file)
--- a/src/cmd/gofmt/rewrite.go
+++ b/src/cmd/gofmt/rewrite.go
@@ -111,15 +111,18 @@ func match(m map[string]reflect.Value, pattern, val reflect.Value) bool {
        if m != nil && pattern.Type() == identType {
                name := pattern.Interface().(*ast.Ident).Name
                if isWildcard(name) {
-                       if old, ok := m[name]; ok {
-                               return match(nil, old, val)
+                       // wildcards only match expressions
+                       if _, ok := val.Interface().(ast.Expr); ok {
+                               if old, ok := m[name]; ok {
+                                       return match(nil, old, val)
+                               }
+                               m[name] = val
+                               return true
                        }
-                       m[name] = val
-                       return true
                }
        }
 
-       // Otherwise, the expressions must match recursively.
+       // Otherwise, pattern and val must match recursively.
        if pattern == nil || val == nil {
                return pattern == nil && val == nil
        }
@@ -204,7 +207,7 @@ func subst(m map[string]reflect.Value, pattern reflect.Value, pos reflect.Value)
 
        if pos != nil && pattern.Type() == positionType {
                // use new position only if old position was valid in the first place
-               if old := pattern.Interface().(token.Position); !old.IsValid() {
+               if old := pattern.Interface().(token.Pos); !old.IsValid() {
                        return pattern
                }
                return pos