Track depths on deduped children

Fixes a very specific error case where deduped children won’t receive the depths object due to it being omitted by the caller when optimizing.

Fixes #926

lib/handlebars/compiler/javascript-compiler.js

@@ -696,6 +696,8 @@ JavaScriptCompiler.prototype = {
       } else {
         child.index = index;
         child.name = 'program' + index;
+
+        this.useDepths = this.useDepths || child.depths.list.length;
       }
     }
   },

spec/regressions.js

@@ -1,4 +1,4 @@
-/*global CompilerContext, Handlebars, shouldCompileTo, shouldThrow */
+/*global CompilerContext, shouldCompileTo, shouldThrow */
 describe('Regressions', function() {
   it("GH-94: Cannot read property of undefined", function() {
     var data = {"books":[{"title":"The origin of species","author":{"name":"Charles Darwin"}},{"title":"Lazarillo de Tormes"}]};
@@ -145,4 +145,21 @@ describe('Regressions', function() {
 
     shouldCompileTo('{{str bar.baz}}', [{}, helpers], 'undefined');
   });
+
+  it('GH-926: Depths and de-dupe', function() {
+    var context = {
+      name: 'foo',
+      data: [
+        1
+      ],
+      notData: [
+        1
+      ]
+    };
+
+    var template = CompilerContext.compile('{{#if dater}}{{#each data}}{{../name}}{{/each}}{{else}}{{#each notData}}{{../name}}{{/each}}{{/if}}');
+
+    var result = template(context);
+    equals(result, 'foo');
+  });
 });