Support 'on T' catch clauses and multiple clauses.

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

 // Copyright (c) 2013, 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 dart2js.ir_builder_task;
 
 import '../closure.dart' as closurelib;
 import '../closure.dart' hide ClosureScope;
 import '../constants/expressions.dart';
 import '../dart_types.dart';
@@ skipping 485 matching lines @@
   //
   // Return without a subexpression is translated as if it were return null.
   ir.Primitive visitReturn(ast.Return node) {
     assert(irBuilder.isOpen);
     assert(invariant(node, node.beginToken.value != 'native'));
     irBuilder.buildReturn(build(node.expression));
     return null;
   }
 
   visitTryStatement(ast.TryStatement node) {
-    // Multiple catch blocks are not yet implemented.
-    if (node.catchBlocks.isEmpty ||
-        !node.catchBlocks.nodes.tail.isEmpty) {
-      return giveup(node, 'not exactly one catch block');
-    }
-    // 'on T' catch blocks are not yet implemented.
-    if ((node.catchBlocks.nodes.head as ast.CatchBlock).onKeyword != null) {
-      return giveup(node, '"on T" catch block');
-    }
     // Finally blocks are not yet implemented.
     if (node.finallyBlock != null) {
       return giveup(node, 'try/finally');
     }
 
     List<CatchClauseInfo> catchClauseInfos = <CatchClauseInfo>[];
     for (ast.CatchBlock catchClause in node.catchBlocks.nodes) {
       assert(catchClause.exception != null);
       LocalVariableElement exceptionVariable = elements[catchClause.exception];
       LocalVariableElement stackTraceVariable;
       if (catchClause.trace != null) {
         stackTraceVariable = elements[catchClause.trace];
       }
+      DartType type;
+      if (catchClause.onKeyword != null) {
+        type = elements.getType(catchClause.type);
+      }
       catchClauseInfos.add(new CatchClauseInfo(
+          type: type,
           exceptionVariable: exceptionVariable,
           stackTraceVariable: stackTraceVariable,
           buildCatchBlock: subbuild(catchClause.block)));
     }
 
     irBuilder.buildTry(
         tryStatementInfo: tryStatements[node],
         buildTryBlock: subbuild(node.tryBlock),
         catchClauseInfos: catchClauseInfos);
   }
@@ skipping 2367 matching lines @@
     node.body = replacementFor(node.body);
   }
 }
 
 /// Visit a just-deleted subterm and unlink all [Reference]s in it.
 class RemovalVisitor extends ir.RecursiveVisitor {
   processReference(ir.Reference reference) {
     reference.unlink();
   }
 }