Rationalize coercions

test/codegen/expect/fieldtest.txt

Index: test/codegen/expect/fieldtest.txt
diff --git a/test/codegen/expect/fieldtest.txt b/test/codegen/expect/fieldtest.txt
index fce05fa9fcb24b9b6b53c0f581e92ce95b40eb57..351d25fa40cbd1a118e15231805e22818bbb23de 100644
--- a/test/codegen/expect/fieldtest.txt
+++ b/test/codegen/expect/fieldtest.txt
@@ -2,12 +2,12 @@
 warning: line 23, column 9 of test/codegen/fieldtest.dart: [DynamicInvoke] a.x requires dynamic invoke
   print(a.x);
         ^^^
-info: line 24, column 10 of test/codegen/fieldtest.dart: [DownCast] a.x (dynamic) will need runtime check to cast to type int
+info: line 24, column 10 of test/codegen/fieldtest.dart: [DynamicCast] a.x (dynamic) will need runtime check to cast to type int
   return a.x;
          ^^^
 warning: line 24, column 10 of test/codegen/fieldtest.dart: [DynamicInvoke] a.x requires dynamic invoke
   return a.x;
          ^^^
-info: line 35, column 7 of test/codegen/fieldtest.dart: [DownCast] value (dynamic) will need runtime check to cast to type int
+info: line 35, column 7 of test/codegen/fieldtest.dart: [DynamicCast] value (dynamic) will need runtime check to cast to type int
   y = value;
       ^^^^^