Remove BlockExpression from the Kernel language.

lib/ast.dart

 // Copyright (c) 2016, 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.
 
 /// -----------------------------------------------------------------------
 ///                           ERROR HANDLING
 /// -----------------------------------------------------------------------
 ///
 /// As a rule of thumb, errors that can be detected statically are handled by
 /// the frontend, typically by translating the erroneous code into a 'throw' or
@@ skipping 2393 matching lines @@
       variable = variable.accept(v);
       variable?.parent = this;
     }
     if (body != null) {
       body = body.accept(v);
       body?.parent = this;
     }
   }
 }
 
-class BlockExpression extends Expression {
-  Block body;
-  Expression value;
-
-  BlockExpression(this.body, this.value) {
-    body?.parent = this;
-    value?.parent = this;
-  }
-
-  DartType getStaticType(TypeEnvironment types) => value.getStaticType(types);
-
-  accept(ExpressionVisitor v) => v.visitBlockExpression(this);
-
-  visitChildren(Visitor v) {
-    body?.accept(v);
-    value?.accept(v);
-  }
-
-  transformChildren(Transformer v) {
-    if (body != null) {
-      body = body.accept(v);
-      body?.parent = this;
-    }
-    if (value != null) {
-      value = value.accept(v);
-      value?.parent = this;
-    }
-  }
-}
-
 // ------------------------------------------------------------------------
 //                              STATEMENTS
 // ------------------------------------------------------------------------
 
 abstract class Statement extends TreeNode {
   accept(StatementVisitor v);
 }
 
 /// A statement with a compile-time error.
 ///
@@ skipping 1188 matching lines @@
 
   @override
   defaultTreeNode(TreeNode node) {
     if (node == child) {
       return replacement;
     } else {
       return node;
     }
   }
 }