Don't inline methods that only throw.

pkg/compiler/lib/src/cps_ir/inline.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library cps_ir.optimization.inline;
 
 import 'cps_fragment.dart';
 import 'cps_ir_builder.dart' show ThisParameterLocal;
 import 'cps_ir_nodes.dart';
 import 'optimizers.dart';
@@ skipping 354 matching lines @@
     // targets containing a try statement.
     if (!target.hasNode) return null;
     if (target.asyncMarker != AsyncMarker.SYNC) return null;
     // V8 does not optimize functions containing a try statement.  Inlining
     // code containing a try statement will make the optimizable calling code
     // become unoptimizable.
     if (target.resolvedAst.elements.containsTryStatement) {
       return null;
     }
 
+    // Don't inline methods that never return. They are usually helper functions
+    // that throw an exception.
+    if (invoke.type.isEmpty && !invoke.type.isNullable) {
+      // TODO(sra): It would be ok to inline if doing so was shrinking.
+      return null;
+    }
+
     Reference<Primitive> dartReceiver = invoke.dartReceiverReference;
     TypeMask abstractReceiver =
         dartReceiver == null ? null : abstractType(dartReceiver);
     // The receiver is non-null in a method body, unless the receiver is known
     // to be `null` (isEmpty covers `null` and unreachable).
     TypeMask abstractReceiverInMethod = abstractReceiver == null
         ? null
         : abstractReceiver.isEmpty
             ? abstractReceiver
             : abstractReceiver.nonNullable();
@@ skipping 142 matching lines @@
       // We cannot inline a constructor invocation containing type arguments
       // because CreateInstance in the body does not know the type arguments.
       // We would incorrectly instantiate a class like A instead of A<B>.
       // TODO(kmillikin): try to fix this.
       GenericType generic = node.dartType;
       if (generic.typeArguments.any((DartType t) => !t.isDynamic)) return null;
     }
     return tryInlining(node, node.target, null);
   }
 }