check ld.Context directly and return if canceled

Author: mmirolim

go/packages/packages.go

@@ -647,18 +647,15 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 }
 wg.Wait()
 }
-
+// check is context still valid
+if ld.Context.Err() != nil {
+return nil, ld.Context.Err()
+}
 result := make([]*Package, len(initial))
 for i, lpkg := range initial {
 result[i] = lpkg.Package
 }
 for i := range ld.pkgs {
-// return err on loading canceled by context
-numErrs := len(ld.pkgs[i].Errors)
-if numErrs > 0 &&
-ld.pkgs[i].Errors[numErrs-1].Kind == ContextCancelError {
-return nil, context.Canceled
-}
 // Clear all unrequested fields, for extra de-Hyrum-ization.
 if ld.requestedMode&NeedName == 0 {
 ld.pkgs[i].Name = ""