Jump past disjoint package on disjoint constraint.

sdk/lib/_internal/pub/lib/src/solver/backtracking_solver.dart

Index: sdk/lib/_internal/pub/lib/src/solver/backtracking_solver.dart
diff --git a/sdk/lib/_internal/pub/lib/src/solver/backtracking_solver.dart b/sdk/lib/_internal/pub/lib/src/solver/backtracking_solver.dart
index 1338b63a563730e7a19b093d5014f7298d25dadf..00a6ba26ef44e1b41a294e5de2560b1a85d6068b 100644
--- a/sdk/lib/_internal/pub/lib/src/solver/backtracking_solver.dart
+++ b/sdk/lib/_internal/pub/lib/src/solver/backtracking_solver.dart
@@ -518,7 +518,7 @@ class Traverser {
     // See if it's possible for a package to match that constraint.
     if (constraint.isEmpty) {
       _solver.logSolve('disjoint constraints on ${dep.name}');
-      throw new DisjointConstraintException(dep.name, dependencies);
+      throw new DisjointConstraintException(depender, dependencies);
     }
 
     return constraint;