Convert closures in all initializers, and share the context between them.

pkg/kernel/lib/transformations/argument_extraction_for_redirecting.dart

Index: pkg/kernel/lib/transformations/argument_extraction_for_redirecting.dart
diff --git a/pkg/kernel/lib/transformations/argument_extraction_for_redirecting.dart b/pkg/kernel/lib/transformations/argument_extraction_for_redirecting.dart
index 39cb7e230c674bcf61d301fdfeb58642214170bd..a1a41427dcbede3351115125489eae841ba96d65 100644
--- a/pkg/kernel/lib/transformations/argument_extraction_for_redirecting.dart
+++ b/pkg/kernel/lib/transformations/argument_extraction_for_redirecting.dart
@@ -2,65 +2,68 @@
 // 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 kernel.transformations.argument_extraction_for_redirecting;
+library kernel.transformations.argument_extraction;
 
 import '../ast.dart'
     show
-        Program,
         Constructor,
-        RedirectingInitializer,
+        FieldInitializer,
+        Initializer,
         Library,
         LocalInitializer,
+        Program,
         VariableDeclaration,
-        VariableGet,
-        Expression,
-        NamedExpression;
+        VariableGet;
 import '../core_types.dart' show CoreTypes;
 import '../visitor.dart' show Transformer;
 
 Program transformProgram(CoreTypes coreTypes, Program program) {
-  new ArgumentExtractionForRedirecting().visitProgram(program);
+  new ArgumentExtractionForTesting().visitProgram(program);
   return program;
 }
 
 void transformLibraries(CoreTypes coreTypes, List<Library> libraries) {
-  var transformer = new ArgumentExtractionForRedirecting();
+  var transformer = new ArgumentExtractionForTesting();
   for (var library in libraries) {
     transformer.visitLibrary(library);
   }
 }
 
-class ArgumentExtractionForRedirecting extends Transformer {
+class ArgumentExtractionForTesting extends Transformer {
   visitConstructor(Constructor node) {
-    if (node.initializers.length == 1 &&
-        node.initializers[0] is RedirectingInitializer) {
-      int index = 0;
-      RedirectingInitializer redirectingInitializer = node.initializers[0];
-      List<Expression> positionalArguments =
-          redirectingInitializer.arguments.positional;
-      List<NamedExpression> namedArguments =
-          redirectingInitializer.arguments.named;
-      for (int i = 0; i < positionalArguments.length; i++) {
-        Expression argument = positionalArguments[i];
-        VariableDeclaration extractedArgument =
-            new VariableDeclaration("extracted#$index", initializer: argument);
-        LocalInitializer initializer = new LocalInitializer(extractedArgument)
-          ..parent = node;
-        node.initializers.insert(index++, initializer);
-        positionalArguments[i] = new VariableGet(extractedArgument)
-          ..parent = redirectingInitializer.arguments;
-      }
-      for (int i = 0; i < namedArguments.length; i++) {
-        Expression argument = namedArguments[i].value;
-        VariableDeclaration extractedArgument =
-            new VariableDeclaration("extracted#$index", initializer: argument);
-        LocalInitializer initializer = new LocalInitializer(extractedArgument)
-          ..parent = node;
-        node.initializers.insert(index++, initializer);
-        namedArguments[i].value = new VariableGet(extractedArgument)
-          ..parent = redirectingInitializer.arguments;
+    var newInits = <Initializer>[];
+
+    int i = 0;

[Dmitry Stefantsov, 2017/07/14 00:34:17]

[i] is not a counter of a loop, so I guess it should have a more descriptive
name.

[sjindel, 2017/07/14 08:49:45]

Done.

+    for (var fi in node.initializers) {

[Dmitry Stefantsov, 2017/07/14 00:34:17]

Please, use a more descriptive name in place of [fi] as well.

[sjindel, 2017/07/14 08:49:45]

Done.

+      if (fi is FieldInitializer) {
+        if (!fi.field.name.name.endsWith("_li")) {
+          newInits.add(fi);
+          continue;

[Dmitry Stefantsov, 2017/07/14 00:34:17]

I think `continue` here doesn't help to eliminate all non-special cases; we do
have an `else` below anyway.  How about structuring the code like this:

```
int variableCounter = 0; // Previously known as [i].
for (var initializer in node.initializers) {
  if (initializer is FieldInitializer
      && initializer.field.name.name.endsWith("_li")) {
    // ... dealing with LocalInitializer here ...
    ++variableCounter;
  }
  newInits.add(initializer);
}
```

[sjindel, 2017/07/14 08:49:45]

Done.

+        }
+
+        // Move the body of the initializer to a new local initializer, and
+        // eta-expand the reference to the local initializer in the body of the
+        // field initializer.
+
+        var value = fi.value;
+
+        var decl = new VariableDeclaration('#li_$i');
+        decl.initializer = value;
+        var li = new LocalInitializer(decl);

[Dmitry Stefantsov, 2017/07/14 00:34:17]

Please, use a more descriptive name in place of [li].

[sjindel, 2017/07/14 08:49:45]

Done.

+        li.parent = node;
+        newInits.add(li);
+
+        fi.value = new VariableGet(decl);
+        fi.value.parent = fi;
+
+        ++i;
+        newInits.add(fi);
+      } else {
+        newInits.add(fi);
       }
     }
+
+    node.initializers = newInits;
     return super.visitConstructor(node);
   }
 }