chore: remove unreadable blocks and use comments instead.

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsStatementTransformer.kt

@@ -16,6 +16,7 @@ import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
 import org.jetbrains.kotlin.ir.symbols.IrReturnableBlockSymbol
 import org.jetbrains.kotlin.ir.types.classifierOrNull
+import org.jetbrains.kotlin.ir.types.classOrNull
 import org.jetbrains.kotlin.ir.types.isAny
 import org.jetbrains.kotlin.ir.util.constructedClassType
 import org.jetbrains.kotlin.ir.util.file
@@ -40,14 +41,29 @@ class IrElementToJsStatementTransformer : BaseIrElementToJsNodeTransformer<JsSta
             context.newFile(it.owner.file, context.currentFunction, context.localNames)
         } ?: context
 
-        val block = JsBlock(expression.statements.map { it.accept(this, newContext) })
+        val statements = expression.statements.map { it.accept(this, newContext) }
 
-        if (expression is IrReturnableBlock) {
+        return if (expression is IrReturnableBlock) {
             val label = context.getNameForReturnableBlock(expression)
-            if (label != null) return JsLabel(label, block)
+            val wrappedStatements = statements.wrapInCommentsInlineFunctionCall(expression)
-        }
 
-        return block
+            if (label != null) {
+                JsLabel(label, JsBlock(wrappedStatements))
+            } else {
+                JsVirtualBlock(wrappedStatements)
+            }
+        } else {
+            JsBlock(statements)
+        }
+    }
+
+    private fun List<JsStatement>.wrapInCommentsInlineFunctionCall(expression: IrReturnableBlock): List<JsStatement> {
+        val inlineFunctionSymbol = expression.inlineFunctionSymbol ?: return this
+        val owner = inlineFunctionSymbol.owner
+        val receiver = (owner.dispatchReceiverParameter ?: owner.extensionReceiverParameter)?.type?.classOrNull?.owner
+        val receiverName = receiver?.name?.asString()?.plus(".") ?: ""
+        val funName = "$receiverName${owner.name}"
+        return listOf(JsSingleLineComment(" Inline function '$funName' call")) + this
     }
 
     override fun visitComposite(expression: IrComposite, context: JsGenerationContext): JsStatement {

js/js.ast/src/org/jetbrains/kotlin/js/backend/JsToStringGenerationVisitor.java

@@ -1275,7 +1275,7 @@ public class JsToStringGenerationVisitor extends JsVisitor {
 
         sourceLocationConsumer.pushSourceInfo(null);
 
-        boolean needBraces = !x.isGlobalBlock();
+        boolean needBraces = !x.isGlobalBlock() && !x.isVirtualBlock();
         if (needBraces) {
             blockOpen();
         }

js/js.ast/src/org/jetbrains/kotlin/js/backend/ast/JsBlock.java

@@ -47,6 +47,8 @@ public class JsBlock extends SourceInfoAwareJsNode implements JsStatement {
         return false;
     }
 
+    public boolean isVirtualBlock() { return false; }
+
     @Override
     public void accept(JsVisitor v) {
         v.visitBlock(this);

js/js.ast/src/org/jetbrains/kotlin/js/backend/ast/JsVirtualBlock.kt

@@ -0,0 +1,23 @@
+// Copyright (c) 2011, 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.
+
+package org.jetbrains.kotlin.js.backend.ast;
+import org.jetbrains.kotlin.js.util.AstUtil;
+
+
+/**
+ * Represents a JavaScript block in the global scope.
+ */
+class JsVirtualBlock(statements: List<JsStatement> = emptyList()) : JsBlock(statements) {
+    override fun isVirtualBlock(): Boolean {
+        return true
+    }
+
+    override fun deepCopy(): JsVirtualBlock  {
+        val globalBlockCopy = JsVirtualBlock()
+        val statementscopy = AstUtil.deepCopy(statements);
+        globalBlockCopy.statements.addAll(statementscopy);
+        return globalBlockCopy.withMetadataFrom(this);
+    }
+}

js/js.serializer/src/js-ast.proto

@@ -254,6 +254,7 @@ message Statement {
         Try try_statement = 37;
         Empty empty = 38;
         SingleLineComment single_line_comment = 39;
+        VirtualBlock virtual_block = 40;
     }
 }
 
@@ -302,6 +303,10 @@ message GlobalBlock {
     repeated Statement statement = 1;
 }
 
+message VirtualBlock {
+    repeated Statement statement = 1;
+}
+
 message Label {
     required int32 nameId = 1;
     required Statement inner_statement = 2;

js/js.serializer/src/org/jetbrains/kotlin/serialization/js/ast/JsAstDeserializerBase.kt

@@ -73,6 +73,10 @@ abstract class JsAstDeserializerBase {
             block
         }
 
+        JsAstProtoBuf.Statement.StatementCase.VIRTUAL_BLOCK -> {
+            JsVirtualBlock(proto.virtualBlock.statementList.map { deserialize(it) })
+        }
+
         JsAstProtoBuf.Statement.StatementCase.GLOBAL_BLOCK -> {
             deserializeGlobalBlock(proto.globalBlock)
         }

js/js.serializer/src/org/jetbrains/kotlin/serialization/js/ast/JsAstProtoBuf.java

@@ -15664,6 +15664,15 @@ public final class JsAstProtoBuf {
      * <code>optional .org.jetbrains.kotlin.serialization.js.ast.SingleLineComment single_line_comment = 39;</code>
      */
     org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.SingleLineComment getSingleLineComment();
+
+    /**
+     * <code>optional .org.jetbrains.kotlin.serialization.js.ast.VirtualBlock virtual_block = 40;</code>
+     */
+    boolean hasVirtualBlock();
+    /**
+     * <code>optional .org.jetbrains.kotlin.serialization.js.ast.VirtualBlock virtual_block = 40;</code>
+     */
+    org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock getVirtualBlock();
   }
   /**
    * Protobuf type {@code org.jetbrains.kotlin.serialization.js.ast.Statement}
@@ -15985,6 +15994,19 @@ public final class JsAstProtoBuf {
               statementCase_ = 39;
               break;
             }
+            case 322: {
+              org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock.Builder subBuilder = null;
+              if (statementCase_ == 40) {
+                subBuilder = ((org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock) statement_).toBuilder();
+              }
+              statement_ = input.readMessage(org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock.PARSER, extensionRegistry);
+              if (subBuilder != null) {
+                subBuilder.mergeFrom((org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock) statement_);
+                statement_ = subBuilder.buildPartial();
+              }
+              statementCase_ = 40;
+              break;
+            }
           }
         }
       } catch (org.jetbrains.kotlin.protobuf.InvalidProtocolBufferException e) {
@@ -16042,6 +16064,7 @@ public final class JsAstProtoBuf {
       TRY_STATEMENT(37),
       EMPTY(38),
       SINGLE_LINE_COMMENT(39),
+      VIRTUAL_BLOCK(40),
       STATEMENT_NOT_SET(0);
       private int value = 0;
       private StatementCase(int value) {
@@ -16068,6 +16091,7 @@ public final class JsAstProtoBuf {
           case 37: return TRY_STATEMENT;
           case 38: return EMPTY;
           case 39: return SINGLE_LINE_COMMENT;
+          case 40: return VIRTUAL_BLOCK;
           case 0: return STATEMENT_NOT_SET;
           default: throw new java.lang.IllegalArgumentException(
             "Value is undefined for this oneof enum.");
@@ -16452,6 +16476,23 @@ public final class JsAstProtoBuf {
       return org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.SingleLineComment.getDefaultInstance();
     }
 
+    public static final int VIRTUAL_BLOCK_FIELD_NUMBER = 40;
+    /**
+     * <code>optional .org.jetbrains.kotlin.serialization.js.ast.VirtualBlock virtual_block = 40;</code>
+     */
+    public boolean hasVirtualBlock() {
+      return statementCase_ == 40;
+    }
+    /**
+     * <code>optional .org.jetbrains.kotlin.serialization.js.ast.VirtualBlock virtual_block = 40;</code>
+     */
+    public org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock getVirtualBlock() {
+      if (statementCase_ == 40) {
+         return (org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock) statement_;
+      }
+      return org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock.getDefaultInstance();
+    }
+
     private void initFields() {
       fileId_ = 0;
       location_ = org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Location.getDefaultInstance();
@@ -16559,6 +16600,12 @@ public final class JsAstProtoBuf {
           return false;
         }
       }
+      if (hasVirtualBlock()) {
+        if (!getVirtualBlock().isInitialized()) {
+          memoizedIsInitialized = 0;
+          return false;
+        }
+      }
       memoizedIsInitialized = 1;
       return true;
     }
@@ -16632,6 +16679,9 @@ public final class JsAstProtoBuf {
       if (statementCase_ == 39) {
         output.writeMessage(39, (org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.SingleLineComment) statement_);
       }
+      if (statementCase_ == 40) {
+        output.writeMessage(40, (org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock) statement_);
+      }
       output.writeRawBytes(unknownFields);
     }
 
@@ -16729,6 +16779,10 @@ public final class JsAstProtoBuf {
         size += org.jetbrains.kotlin.protobuf.CodedOutputStream
           .computeMessageSize(39, (org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.SingleLineComment) statement_);
       }
+      if (statementCase_ == 40) {
+        size += org.jetbrains.kotlin.protobuf.CodedOutputStream
+          .computeMessageSize(40, (org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock) statement_);
+      }
       size += unknownFields.size();
       memoizedSerializedSize = size;
       return size;
@@ -16923,6 +16977,9 @@ public final class JsAstProtoBuf {
         if (statementCase_ == 39) {
           result.statement_ = statement_;
         }
+        if (statementCase_ == 40) {
+          result.statement_ = statement_;
+        }
         result.bitField0_ = to_bitField0_;
         result.statementCase_ = statementCase_;
         return result;
@@ -17016,6 +17073,10 @@ public final class JsAstProtoBuf {
             mergeSingleLineComment(other.getSingleLineComment());
             break;
           }
+          case VIRTUAL_BLOCK: {
+            mergeVirtualBlock(other.getVirtualBlock());
+            break;
+          }
           case STATEMENT_NOT_SET: {
             break;
           }
@@ -17122,6 +17183,12 @@ public final class JsAstProtoBuf {
             return false;
           }
         }
+        if (hasVirtualBlock()) {
+          if (!getVirtualBlock().isInitialized()) {
+            
+            return false;
+          }
+        }
         return true;
       }
 
@@ -18498,6 +18565,70 @@ public final class JsAstProtoBuf {
         return this;
       }
 
+      /**
+       * <code>optional .org.jetbrains.kotlin.serialization.js.ast.VirtualBlock virtual_block = 40;</code>
+       */
+      public boolean hasVirtualBlock() {
+        return statementCase_ == 40;
+      }
+      /**
+       * <code>optional .org.jetbrains.kotlin.serialization.js.ast.VirtualBlock virtual_block = 40;</code>
+       */
+      public org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock getVirtualBlock() {
+        if (statementCase_ == 40) {
+          return (org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock) statement_;
+        }
+        return org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock.getDefaultInstance();
+      }
+      /**
+       * <code>optional .org.jetbrains.kotlin.serialization.js.ast.VirtualBlock virtual_block = 40;</code>
+       */
+      public Builder setVirtualBlock(org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock value) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        statement_ = value;
+
+        statementCase_ = 40;
+        return this;
+      }
+      /**
+       * <code>optional .org.jetbrains.kotlin.serialization.js.ast.VirtualBlock virtual_block = 40;</code>
+       */
+      public Builder setVirtualBlock(
+          org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock.Builder builderForValue) {
+        statement_ = builderForValue.build();
+
+        statementCase_ = 40;
+        return this;
+      }
+      /**
+       * <code>optional .org.jetbrains.kotlin.serialization.js.ast.VirtualBlock virtual_block = 40;</code>
+       */
+      public Builder mergeVirtualBlock(org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock value) {
+        if (statementCase_ == 40 &&
+            statement_ != org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock.getDefaultInstance()) {
+          statement_ = org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock.newBuilder((org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock) statement_)
+              .mergeFrom(value).buildPartial();
+        } else {
+          statement_ = value;
+        }
+
+        statementCase_ = 40;
+        return this;
+      }
+      /**
+       * <code>optional .org.jetbrains.kotlin.serialization.js.ast.VirtualBlock virtual_block = 40;</code>
+       */
+      public Builder clearVirtualBlock() {
+        if (statementCase_ == 40) {
+          statementCase_ = 0;
+          statement_ = null;
+          
+        }
+        return this;
+      }
+
       // @@protoc_insertion_point(builder_scope:org.jetbrains.kotlin.serialization.js.ast.Statement)
     }
 
@@ -23095,6 +23226,499 @@ public final class JsAstProtoBuf {
     // @@protoc_insertion_point(class_scope:org.jetbrains.kotlin.serialization.js.ast.GlobalBlock)
   }
 
+  public interface VirtualBlockOrBuilder extends
+      // @@protoc_insertion_point(interface_extends:org.jetbrains.kotlin.serialization.js.ast.VirtualBlock)
+      org.jetbrains.kotlin.protobuf.MessageLiteOrBuilder {
+
+    /**
+     * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+     */
+    java.util.List<org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement> 
+        getStatementList();
+    /**
+     * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+     */
+    org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement getStatement(int index);
+    /**
+     * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+     */
+    int getStatementCount();
+  }
+  /**
+   * Protobuf type {@code org.jetbrains.kotlin.serialization.js.ast.VirtualBlock}
+   */
+  public static final class VirtualBlock extends
+      org.jetbrains.kotlin.protobuf.GeneratedMessageLite implements
+      // @@protoc_insertion_point(message_implements:org.jetbrains.kotlin.serialization.js.ast.VirtualBlock)
+      VirtualBlockOrBuilder {
+    // Use VirtualBlock.newBuilder() to construct.
+    private VirtualBlock(org.jetbrains.kotlin.protobuf.GeneratedMessageLite.Builder builder) {
+      super(builder);
+      this.unknownFields = builder.getUnknownFields();
+    }
+    private VirtualBlock(boolean noInit) { this.unknownFields = org.jetbrains.kotlin.protobuf.ByteString.EMPTY;}
+
+    private static final VirtualBlock defaultInstance;
+    public static VirtualBlock getDefaultInstance() {
+      return defaultInstance;
+    }
+
+    public VirtualBlock getDefaultInstanceForType() {
+      return defaultInstance;
+    }
+
+    private final org.jetbrains.kotlin.protobuf.ByteString unknownFields;
+    private VirtualBlock(
+        org.jetbrains.kotlin.protobuf.CodedInputStream input,
+        org.jetbrains.kotlin.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws org.jetbrains.kotlin.protobuf.InvalidProtocolBufferException {
+      initFields();
+      int mutable_bitField0_ = 0;
+      org.jetbrains.kotlin.protobuf.ByteString.Output unknownFieldsOutput =
+          org.jetbrains.kotlin.protobuf.ByteString.newOutput();
+      org.jetbrains.kotlin.protobuf.CodedOutputStream unknownFieldsCodedOutput =
+          org.jetbrains.kotlin.protobuf.CodedOutputStream.newInstance(
+              unknownFieldsOutput, 1);
+      try {
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            default: {
+              if (!parseUnknownField(input, unknownFieldsCodedOutput,
+                                     extensionRegistry, tag)) {
+                done = true;
+              }
+              break;
+            }
+            case 10: {
+              if (!((mutable_bitField0_ & 0x00000001) == 0x00000001)) {
+                statement_ = new java.util.ArrayList<org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement>();
+                mutable_bitField0_ |= 0x00000001;
+              }
+              statement_.add(input.readMessage(org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement.PARSER, extensionRegistry));
+              break;
+            }
+          }
+        }
+      } catch (org.jetbrains.kotlin.protobuf.InvalidProtocolBufferException e) {
+        throw e.setUnfinishedMessage(this);
+      } catch (java.io.IOException e) {
+        throw new org.jetbrains.kotlin.protobuf.InvalidProtocolBufferException(
+            e.getMessage()).setUnfinishedMessage(this);
+      } finally {
+        if (((mutable_bitField0_ & 0x00000001) == 0x00000001)) {
+          statement_ = java.util.Collections.unmodifiableList(statement_);
+        }
+        try {
+          unknownFieldsCodedOutput.flush();
+        } catch (java.io.IOException e) {
+        // Should not happen
+        } finally {
+          unknownFields = unknownFieldsOutput.toByteString();
+        }
+        makeExtensionsImmutable();
+      }
+    }
+    public static org.jetbrains.kotlin.protobuf.Parser<VirtualBlock> PARSER =
+        new org.jetbrains.kotlin.protobuf.AbstractParser<VirtualBlock>() {
+      public VirtualBlock parsePartialFrom(
+          org.jetbrains.kotlin.protobuf.CodedInputStream input,
+          org.jetbrains.kotlin.protobuf.ExtensionRegistryLite extensionRegistry)
+          throws org.jetbrains.kotlin.protobuf.InvalidProtocolBufferException {
+        return new VirtualBlock(input, extensionRegistry);
+      }
+    };
+
+    @java.lang.Override
+    public org.jetbrains.kotlin.protobuf.Parser<VirtualBlock> getParserForType() {
+      return PARSER;
+    }
+
+    public static final int STATEMENT_FIELD_NUMBER = 1;
+    private java.util.List<org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement> statement_;
+    /**
+     * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+     */
+    public java.util.List<org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement> getStatementList() {
+      return statement_;
+    }
+    /**
+     * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+     */
+    public java.util.List<? extends org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.StatementOrBuilder> 
+        getStatementOrBuilderList() {
+      return statement_;
+    }
+    /**
+     * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+     */
+    public int getStatementCount() {
+      return statement_.size();
+    }
+    /**
+     * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+     */
+    public org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement getStatement(int index) {
+      return statement_.get(index);
+    }
+    /**
+     * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+     */
+    public org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.StatementOrBuilder getStatementOrBuilder(
+        int index) {
+      return statement_.get(index);
+    }
+
+    private void initFields() {
+      statement_ = java.util.Collections.emptyList();
+    }
+    private byte memoizedIsInitialized = -1;
+    public final boolean isInitialized() {
+      byte isInitialized = memoizedIsInitialized;
+      if (isInitialized == 1) return true;
+      if (isInitialized == 0) return false;
+
+      for (int i = 0; i < getStatementCount(); i++) {
+        if (!getStatement(i).isInitialized()) {
+          memoizedIsInitialized = 0;
+          return false;
+        }
+      }
+      memoizedIsInitialized = 1;
+      return true;
+    }
+
+    public void writeTo(org.jetbrains.kotlin.protobuf.CodedOutputStream output)
+                        throws java.io.IOException {
+      getSerializedSize();
+      for (int i = 0; i < statement_.size(); i++) {
+        output.writeMessage(1, statement_.get(i));
+      }
+      output.writeRawBytes(unknownFields);
+    }
+
+    private int memoizedSerializedSize = -1;
+    public int getSerializedSize() {
+      int size = memoizedSerializedSize;
+      if (size != -1) return size;
+
+      size = 0;
+      for (int i = 0; i < statement_.size(); i++) {
+        size += org.jetbrains.kotlin.protobuf.CodedOutputStream
+          .computeMessageSize(1, statement_.get(i));
+      }
+      size += unknownFields.size();
+      memoizedSerializedSize = size;
+      return size;
+    }
+
+    private static final long serialVersionUID = 0L;
+    @java.lang.Override
+    protected java.lang.Object writeReplace()
+        throws java.io.ObjectStreamException {
+      return super.writeReplace();
+    }
+
+    public static org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock parseFrom(
+        org.jetbrains.kotlin.protobuf.ByteString data)
+        throws org.jetbrains.kotlin.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data);
+    }
+    public static org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock parseFrom(
+        org.jetbrains.kotlin.protobuf.ByteString data,
+        org.jetbrains.kotlin.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws org.jetbrains.kotlin.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data, extensionRegistry);
+    }
+    public static org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock parseFrom(byte[] data)
+        throws org.jetbrains.kotlin.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data);
+    }
+    public static org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock parseFrom(
+        byte[] data,
+        org.jetbrains.kotlin.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws org.jetbrains.kotlin.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data, extensionRegistry);
+    }
+    public static org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock parseFrom(java.io.InputStream input)
+        throws java.io.IOException {
+      return PARSER.parseFrom(input);
+    }
+    public static org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock parseFrom(
+        java.io.InputStream input,
+        org.jetbrains.kotlin.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      return PARSER.parseFrom(input, extensionRegistry);
+    }
+    public static org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock parseDelimitedFrom(java.io.InputStream input)
+        throws java.io.IOException {
+      return PARSER.parseDelimitedFrom(input);
+    }
+    public static org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock parseDelimitedFrom(
+        java.io.InputStream input,
+        org.jetbrains.kotlin.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      return PARSER.parseDelimitedFrom(input, extensionRegistry);
+    }
+    public static org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock parseFrom(
+        org.jetbrains.kotlin.protobuf.CodedInputStream input)
+        throws java.io.IOException {
+      return PARSER.parseFrom(input);
+    }
+    public static org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock parseFrom(
+        org.jetbrains.kotlin.protobuf.CodedInputStream input,
+        org.jetbrains.kotlin.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      return PARSER.parseFrom(input, extensionRegistry);
+    }
+
+    public static Builder newBuilder() { return Builder.create(); }
+    public Builder newBuilderForType() { return newBuilder(); }
+    public static Builder newBuilder(org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock prototype) {
+      return newBuilder().mergeFrom(prototype);
+    }
+    public Builder toBuilder() { return newBuilder(this); }
+
+    /**
+     * Protobuf type {@code org.jetbrains.kotlin.serialization.js.ast.VirtualBlock}
+     */
+    public static final class Builder extends
+        org.jetbrains.kotlin.protobuf.GeneratedMessageLite.Builder<
+          org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock, Builder>
+        implements
+        // @@protoc_insertion_point(builder_implements:org.jetbrains.kotlin.serialization.js.ast.VirtualBlock)
+        org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlockOrBuilder {
+      // Construct using org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock.newBuilder()
+      private Builder() {
+        maybeForceBuilderInitialization();
+      }
+
+      private void maybeForceBuilderInitialization() {
+      }
+      private static Builder create() {
+        return new Builder();
+      }
+
+      public Builder clear() {
+        super.clear();
+        statement_ = java.util.Collections.emptyList();
+        bitField0_ = (bitField0_ & ~0x00000001);
+        return this;
+      }
+
+      public Builder clone() {
+        return create().mergeFrom(buildPartial());
+      }
+
+      public org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock getDefaultInstanceForType() {
+        return org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock.getDefaultInstance();
+      }
+
+      public org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock build() {
+        org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock result = buildPartial();
+        if (!result.isInitialized()) {
+          throw newUninitializedMessageException(result);
+        }
+        return result;
+      }
+
+      public org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock buildPartial() {
+        org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock result = new org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock(this);
+        int from_bitField0_ = bitField0_;
+        if (((bitField0_ & 0x00000001) == 0x00000001)) {
+          statement_ = java.util.Collections.unmodifiableList(statement_);
+          bitField0_ = (bitField0_ & ~0x00000001);
+        }
+        result.statement_ = statement_;
+        return result;
+      }
+
+      public Builder mergeFrom(org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock other) {
+        if (other == org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock.getDefaultInstance()) return this;
+        if (!other.statement_.isEmpty()) {
+          if (statement_.isEmpty()) {
+            statement_ = other.statement_;
+            bitField0_ = (bitField0_ & ~0x00000001);
+          } else {
+            ensureStatementIsMutable();
+            statement_.addAll(other.statement_);
+          }
+          
+        }
+        setUnknownFields(
+            getUnknownFields().concat(other.unknownFields));
+        return this;
+      }
+
+      public final boolean isInitialized() {
+        for (int i = 0; i < getStatementCount(); i++) {
+          if (!getStatement(i).isInitialized()) {
+            
+            return false;
+          }
+        }
+        return true;
+      }
+
+      public Builder mergeFrom(
+          org.jetbrains.kotlin.protobuf.CodedInputStream input,
+          org.jetbrains.kotlin.protobuf.ExtensionRegistryLite extensionRegistry)
+          throws java.io.IOException {
+        org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock parsedMessage = null;
+        try {
+          parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        } catch (org.jetbrains.kotlin.protobuf.InvalidProtocolBufferException e) {
+          parsedMessage = (org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.VirtualBlock) e.getUnfinishedMessage();
+          throw e;
+        } finally {
+          if (parsedMessage != null) {
+            mergeFrom(parsedMessage);
+          }
+        }
+        return this;
+      }
+      private int bitField0_;
+
+      private java.util.List<org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement> statement_ =
+        java.util.Collections.emptyList();
+      private void ensureStatementIsMutable() {
+        if (!((bitField0_ & 0x00000001) == 0x00000001)) {
+          statement_ = new java.util.ArrayList<org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement>(statement_);
+          bitField0_ |= 0x00000001;
+         }
+      }
+
+      /**
+       * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+       */
+      public java.util.List<org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement> getStatementList() {
+        return java.util.Collections.unmodifiableList(statement_);
+      }
+      /**
+       * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+       */
+      public int getStatementCount() {
+        return statement_.size();
+      }
+      /**
+       * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+       */
+      public org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement getStatement(int index) {
+        return statement_.get(index);
+      }
+      /**
+       * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+       */
+      public Builder setStatement(
+          int index, org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement value) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        ensureStatementIsMutable();
+        statement_.set(index, value);
+
+        return this;
+      }
+      /**
+       * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+       */
+      public Builder setStatement(
+          int index, org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement.Builder builderForValue) {
+        ensureStatementIsMutable();
+        statement_.set(index, builderForValue.build());
+
+        return this;
+      }
+      /**
+       * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+       */
+      public Builder addStatement(org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement value) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        ensureStatementIsMutable();
+        statement_.add(value);
+
+        return this;
+      }
+      /**
+       * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+       */
+      public Builder addStatement(
+          int index, org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement value) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        ensureStatementIsMutable();
+        statement_.add(index, value);
+
+        return this;
+      }
+      /**
+       * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+       */
+      public Builder addStatement(
+          org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement.Builder builderForValue) {
+        ensureStatementIsMutable();
+        statement_.add(builderForValue.build());
+
+        return this;
+      }
+      /**
+       * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+       */
+      public Builder addStatement(
+          int index, org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement.Builder builderForValue) {
+        ensureStatementIsMutable();
+        statement_.add(index, builderForValue.build());
+
+        return this;
+      }
+      /**
+       * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+       */
+      public Builder addAllStatement(
+          java.lang.Iterable<? extends org.jetbrains.kotlin.serialization.js.ast.JsAstProtoBuf.Statement> values) {
+        ensureStatementIsMutable();
+        org.jetbrains.kotlin.protobuf.AbstractMessageLite.Builder.addAll(
+            values, statement_);
+
+        return this;
+      }
+      /**
+       * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+       */
+      public Builder clearStatement() {
+        statement_ = java.util.Collections.emptyList();
+        bitField0_ = (bitField0_ & ~0x00000001);
+
+        return this;
+      }
+      /**
+       * <code>repeated .org.jetbrains.kotlin.serialization.js.ast.Statement statement = 1;</code>
+       */
+      public Builder removeStatement(int index) {
+        ensureStatementIsMutable();
+        statement_.remove(index);
+
+        return this;
+      }
+
+      // @@protoc_insertion_point(builder_scope:org.jetbrains.kotlin.serialization.js.ast.VirtualBlock)
+    }
+
+    static {
+      defaultInstance = new VirtualBlock(true);
+      defaultInstance.initFields();
+    }
+
+    // @@protoc_insertion_point(class_scope:org.jetbrains.kotlin.serialization.js.ast.VirtualBlock)
+  }
+
   public interface LabelOrBuilder extends
       // @@protoc_insertion_point(interface_extends:org.jetbrains.kotlin.serialization.js.ast.Label)
       org.jetbrains.kotlin.protobuf.MessageLiteOrBuilder {

js/js.serializer/src/org/jetbrains/kotlin/serialization/js/ast/JsAstSerializerBase.kt

@@ -67,14 +67,22 @@ abstract class JsAstSerializerBase {
             }
 
             override fun visitBlock(x: JsBlock) {
-                if (x is JsGlobalBlock) {
+                when (x) {
-                    builder.globalBlock = serializeBlock(x)
+                    is JsGlobalBlock -> { builder.globalBlock = serializeBlock(x) }
-                } else {
+                    is JsVirtualBlock -> {
-                    val blockBuilder = JsAstProtoBuf.Block.newBuilder()
+                        val virtualBlockBuilder = JsAstProtoBuf.VirtualBlock.newBuilder()
-                    for (part in x.statements) {
+                        for (part in x.statements) {
-                        blockBuilder.addStatement(serialize(part))
+                            virtualBlockBuilder.addStatement(serialize(part))
+                        }
+                        builder.virtualBlock = virtualBlockBuilder.build()
+                    }
+                    else -> {
+                        val blockBuilder = JsAstProtoBuf.Block.newBuilder()
+                        for (part in x.statements) {
+                            blockBuilder.addStatement(serialize(part))
+                        }
+                        builder.block = blockBuilder.build()
                     }
-                    builder.block = blockBuilder.build()
                 }
             }