libgo: update to Go1.14beta1

[thirdparty/gcc.git] / libgo / go / cmd / gofmt / rewrite.go

diff --git a/libgo/go/cmd/gofmt/rewrite.go b/libgo/go/cmd/gofmt/rewrite.go
index 79b7858a5afd06be14152efdc3cf9d12a4fa1887..bab22e04cdac00284170d792fa7a4812ff769e9d 100644 (file)
--- a/libgo/go/cmd/gofmt/rewrite.go
+++ b/libgo/go/cmd/gofmt/rewrite.go
@@ -271,6 +271,12 @@ func subst(m map[string]reflect.Value, pattern reflect.Value, pos reflect.Value)
        // Otherwise copy.
        switch p := pattern; p.Kind() {
        case reflect.Slice:
+               if p.IsNil() {
+                       // Do not turn nil slices into empty slices. go/ast
+                       // guarantees that certain lists will be nil if not
+                       // populated.
+                       return reflect.Zero(p.Type())
+               }
                v := reflect.MakeSlice(p.Type(), p.Len(), p.Len())
                for i := 0; i < p.Len(); i++ {
                        v.Index(i).Set(subst(m, p.Index(i), pos))