Don't recreate CoreTypes in transformers. Pass it in.

pkg/front_end/lib/src/fasta/kernel/kernel_target.dart

Index: pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
index 2a0f3ffa45332105a4160fb28dcc55377fbe02ec..7841e891ff17949096042281d43e4dfc2458ee12 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
@@ -40,7 +40,6 @@ import 'package:kernel/ast.dart'
         VariableGet,
         VoidType;
 
-import 'package:kernel/core_types.dart' show CoreTypes;
 import 'package:kernel/transformations/erasure.dart' show Erasure;
 
 import 'package:kernel/transformations/continuation.dart' as transformAsync;
@@ -254,6 +253,10 @@ class KernelTarget extends TargetImplementation {
       loader.performInitializerInference();
     } on InputError catch (e) {
       handleInputError(e, isFullProgram: false);
+      // TODO(scheglov) Normally we create CoreTypes and ClassHierarchy.
+      // But if there is an exception, they are not created, and when we later
+      // blindly continue with buildProgram(), we crash.
+      loader.computeHierarchy(_program);
     } catch (e, s) {
       return reportCrash(e, s, loader?.currentUriForCrashReporting);
     }
@@ -662,7 +665,8 @@ class KernelTarget extends TargetImplementation {
   }
 
   void transformMixinApplications() {
-    new MixinFullResolution(backendTarget).transform(_program);
+    new MixinFullResolution(backendTarget, loader.coreTypes)
+        .transform(_program);
     ticker.logMs("Transformed mixin applications");
   }
 
@@ -672,9 +676,8 @@ class KernelTarget extends TargetImplementation {
       _program.accept(new Erasure());
       ticker.logMs("Erased type variables in generic methods");
     }
-    var coreTypes = new CoreTypes(_program);
     // TODO(kmillikin): Make this run on a per-method basis.
-    transformAsync.transformLibraries(coreTypes, loader.libraries);
+    transformAsync.transformLibraries(loader.coreTypes, loader.libraries);
     ticker.logMs("Transformed async methods");
   }
 
@@ -701,7 +704,7 @@ class KernelTarget extends TargetImplementation {
     // TODO(sigmund): replace this step with data that is directly computed from
     // the builders: we should know the tree-shaking roots without having to do
     // a second visit over the tree.
-    new RootsMarker(data).run(_program, isIncluded);
+    new RootsMarker(loader.coreTypes, data).run(_program, isIncluded);
     trimProgram(_program, data, isIncluded);
   }