Split Parameter and TypeParameter out of Identifier

lib/src/js/printer.dart

Index: lib/src/js/printer.dart
diff --git a/lib/src/js/printer.dart b/lib/src/js/printer.dart
index cc347255cb69d824453503dc5aeac5ba30f5cda4..c8eca7aaf988647380fd2cd9eeebbf7789291f14 100644
--- a/lib/src/js/printer.dart
+++ b/lib/src/js/printer.dart
@@ -213,9 +213,15 @@ class Printer extends TypeScriptTypePrinter implements NodeVisitor {
         out(",");
         spaceOut();
       }
-      visitNestedExpression(nodes[i], hasRequiredType,
-                            newInForInit: newInForInit,
-                            newAtStatementBegin: newAtStatementBegin);
+      var node = nodes[i];
+      if (node is Expression) {
+        visitNestedExpression(node, hasRequiredType,
+                              newInForInit: newInForInit,
+                              newAtStatementBegin: newAtStatementBegin);
+      } else {
+        // TODO(ochafik): Precedence of Parameters?
+        visit(node);
+      }
     }
   }
 
@@ -878,12 +884,20 @@ class Printer extends TypeScriptTypePrinter implements NodeVisitor {
 
   visitIdentifier(Identifier node) {
     out(localNamer.getName(node));
+  }
+
+  visitParameter(Parameter node) {
+    if (node.isRest) out('...');
+    visit(node.binding);
     outTypeAnnotation(node.type);
   }
 
-  visitRestParameter(RestParameter node) {
-    out('...');
-    visitIdentifier(node.parameter);
+  visitTypeParameter(TypeParameter node) {
+    visit(node.name);
+    if (node.bound != null && options.shouldEmitTypes) {
+      out(" extends ");
+      visit(node.bound);
+    }
   }
 
   bool isDigit(int charCode) {
@@ -944,10 +958,11 @@ class Printer extends TypeScriptTypePrinter implements NodeVisitor {
 
   visitArrowFun(ArrowFun fun) {
     localNamer.enterScope(fun);
-    if (fun.params.length == 1 &&
+    if (fun.params.length == 1 && fun.params.single.binding is Expression &&
         (fun.params.single.type == null || !options.shouldEmitTypes)) {
-      visitNestedExpression(fun.params.single, SPREAD,
-          newInForInit: false, newAtStatementBegin: false);
+      visit(fun.params.single.binding);
+      // visitNestedExpression(fun.params.single, SPREAD,
+      //     newInForInit: false, newAtStatementBegin: false);
     } else {
       out("(");
       visitCommaSeparated(fun.params, SPREAD,
@@ -1093,7 +1108,7 @@ class Printer extends TypeScriptTypePrinter implements NodeVisitor {
     lineOut();
   }
 
-  void outTypeParams(Iterable<Identifier> typeParams) {
+  void outTypeParams(Iterable<TypeParameter> typeParams) {
     if (typeParams != null && options.shouldEmitTypes && typeParams.isNotEmpty) {
       out("<");
       var first = true;
@@ -1391,7 +1406,18 @@ class VarCollector extends BaseVisitor {
       nested = true;
       if (fun.params != null) {
         for (var param in fun.params) {
-          params.add(param.name);
+          collectBinding(Node node) {
+            if (node is Identifier) {
+              // TODO(ochafik): collect destructured
+              params.add(node.name);
+            } else if (node is DestructuredVariable) {
+              collectBinding(node.name);
+              collectBinding(node.structure);
+            } else if (node is BindingPattern) {
+              node.variables.forEach(collectBinding);
+            }
+          }
+          collectBinding(param.binding);
         }
       }
       fun.body.accept(this);
@@ -1644,12 +1670,13 @@ abstract class VariableDeclarationVisitor<T> extends BaseVisitor<T> {
 
   _scanVariableBinding(VariableBinding d) {
     if (d is Identifier) declare(d);
+    else if (d is Parameter) _scanVariableBinding(d.binding);
     else d.accept(this);
   }
 
-  visitRestParameter(RestParameter node) {
-    _scanVariableBinding(node.parameter);
-    super.visitRestParameter(node);
+  visitParameter(Parameter node) {
+    _scanVariableBinding(node.binding);
+    super.visitParameter(node);
   }
 
   visitDestructuredVariable(DestructuredVariable node) {