Introduce _emitParameterReferences to avoid mixing params with param references.

test/codegen/expect/destructuring.js

Index: test/codegen/expect/destructuring.js
diff --git a/test/codegen/expect/destructuring.js b/test/codegen/expect/destructuring.js
index 7049614851187f60565dafd556bd85c58a9d5676..4558340a586584684e239820ed4894e36a5c1c30 100644
--- a/test/codegen/expect/destructuring.js
+++ b/test/codegen/expect/destructuring.js
@@ -9,10 +9,44 @@ dart_library.library('destructuring', null, /* Imports */[
     f(a, b, c);
   }
   dart.fn(f, dart.dynamic, [core.int, dart.dynamic], [dart.dynamic]);
+  function f_sync(a, b, c = 1) {
+    return dart.syncStar(function*(a, b, c = 1) {
+    }, dart.dynamic, a, b, c);
+  }
+  dart.fn(f_sync, dart.dynamic, [core.int, dart.dynamic], [dart.dynamic]);
+  function f_async(a, b, c = 1) {
+    return dart.asyncStar(function*(stream, a, b, c = 1) {
+    }, dart.dynamic, a, b, c);
+  }
+  dart.fn(f_async, dart.dynamic, [core.int, dart.dynamic], [dart.dynamic]);
   function g(a, b, {c = 1} = {}) {
     f(a, b, c);
   }
   dart.fn(g, dart.dynamic, [core.int, dart.dynamic], {c: dart.dynamic});
+  function g_sync(a, b, {c = 1} = {}) {
+    return dart.syncStar(function*(a, b, {c = 1} = {}) {
+    }, dart.dynamic, a, b, opts);
+  }
+  dart.fn(g_sync, dart.dynamic, [core.int, dart.dynamic], {c: dart.dynamic});
+  function g_async(a, b, {c = 1} = {}) {
+    return dart.asyncStar(function*(stream, a, b, {c = 1} = {}) {
+    }, dart.dynamic, a, b, opts);
+  }
+  dart.fn(g_async, dart.dynamic, [core.int, dart.dynamic], {c: dart.dynamic});
+  function r(a, ...others) {
+    r(a, ...others);
+  }
+  dart.fn(r, dart.dynamic, [core.int, dart.dynamic]);
+  function r_sync(a, ...others) {
+    return dart.syncStar(function*(a, ...others) {
+    }, dart.dynamic, a, ...others);
+  }
+  dart.fn(r_sync, dart.dynamic, [core.int, dart.dynamic]);
+  function r_async(a, ...others) {
+    return dart.asyncStar(function*(stream, a, ...others) {
+    }, dart.dynamic, a, ...others);
+  }
+  dart.fn(r_async, dart.dynamic, [core.int, dart.dynamic]);
   function invalid_names1(let$, func, arguments$) {
     f(let$, func, arguments$);
   }
@@ -31,7 +65,14 @@ dart_library.library('destructuring', null, /* Imports */[
   dart.fn(names_clashing_with_object_props, dart.dynamic, [], {constructor: core.int, valueOf: dart.dynamic, hasOwnProperty: dart.dynamic});
   // Exports:
   exports.f = f;
+  exports.f_sync = f_sync;
+  exports.f_async = f_async;
   exports.g = g;
+  exports.g_sync = g_sync;
+  exports.g_async = g_async;
+  exports.r = r;
+  exports.r_sync = r_sync;
+  exports.r_async = r_async;
   exports.invalid_names1 = invalid_names1;
   exports.invalid_names2 = invalid_names2;
   exports.invalid_names3 = invalid_names3;