Assignment expressions in tree IR.

pkg/compiler/lib/src/tree_ir/tree_ir_integrity.dart

 library tree_ir.integrity;
 
 import 'tree_ir_nodes.dart';
 
 /// Performs integrity checks on the tree_ir.
 ///
 /// Should only be run for debugging purposes, not in production.
 ///
 /// - Reference counts on must match the actual number of references.
 /// - Labels must be in scope when referenced.
@@ skipping 47 matching lines @@
   }
 
   void undeclare(Variable variable) {
     scope.remove(variable);
   }
 
   visitVariableUse(VariableUse node) {
     read(node.variable);
   }
 
+  visitVariableDeclaration(VariableDeclaration node) {
+    visitExpression(node.value);
+    declare(node.variable);
+    visitStatement(node.next);
+    undeclare(node.variable);
+  }
+
   visitAssign(Assign node) {
     visitExpression(node.value);
-    if (node.isDeclaration) {
-      declare(node.variable);
-    } else {
-      write(node.variable);
-    }
-    visitStatement(node.next);
-    if (node.isDeclaration) {
-      undeclare(node.variable);
-    }
+    write(node.variable);
   }
 
   visitTry(Try node) {
     visitStatement(node.tryBody);
     node.catchParameters.forEach(declare);
     visitStatement(node.catchBody);
     node.catchParameters.forEach(undeclare);
   }
 
   visitFunctionDeclaration(FunctionDeclaration node) {
@@ skipping 85 matching lines @@
       if (reads != variable.readCount || writes != variable.writeCount) {
         error('Invalid reference count for $variable:\n'
               '- Variable has $reads reads and $writes writes\n'
               '- Reference count is ${variable.readCount} reads and '
               '${variable.writeCount} writes');
       }
     }
   }
 
 }