A visitor that builds a map from node to "Usage".

tests/language/language.status

Index: tests/language/language.status
diff --git a/tests/language/language.status b/tests/language/language.status
index 3260576db10b192aff8c5f92c92662b6d4120dba..10ecf6deac3f7641c0e0eaa0c8750faf2a6ebb83 100644
--- a/tests/language/language.status
+++ b/tests/language/language.status
@@ -143,17 +143,15 @@ prefix_core_test: Fail # Issue 2264.
 [ $compiler == dart2dart ]
 # Tests that crash after reverting resolution of type variables in default clause.
 # https://chromiumcodereview.appspot.com/10824062/
-default_factory2_test/01: Crash
-default_factory3_test: Crash
-factory2_test: Crash
+default_factory2_test/01: Fail
+default_factory3_test: Fail
 function_type_alias6_test: Crash
-type_variable_scope_test/00: Crash
-type_variable_scope_test/01: Crash
-type_variable_scope_test/02: Crash
-type_variable_scope_test/03: Crash
-type_variable_scope_test/04: Crash
-type_variable_scope_test/05: Crash
-type_variable_scope_test/none: Crash
+type_variable_scope_test/00: Fail
+type_variable_scope_test/01: Fail
+type_variable_scope_test/02: Fail
+type_variable_scope_test/03: Fail
+type_variable_scope_test/04: Fail
+type_variable_scope_test/05: Fail
 # Passes VMOptions, should be supported in test framework.
 assertion_test: Fail
 bootstrap_test: Fail
@@ -301,7 +299,6 @@ prefix14_test: Fail
 prefix15_test: Fail
 prefix18_negative_test: Fail
 prefix20_negative_test: Fail
-prefix21_test: Fail
 private3_test: Fail
 private_member1_negative_test: Fail
 private_member_test: Fail