diff --git a/CHANGELOG.md b/CHANGELOG.md
index 47feb31c..9400ece 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 ## 1.12.0
 
+### Language changes
+
+* Null-aware operators
+    * `??`: if null operator. `expr1 ?? expr2` evaluates to `expr1` if not `null`, otherwise `expr2`.
+    * `??=`: null-aware assignment. `v ??= expr` causes `v` to be assigned `expr` only if `v` is `null`.
+    * `x?.p`: null-aware access. `x?.p` evaluates to `x.p` if `x` is not `null`, otherwise evaluates to `null`.
+    * `x?.m()`: null-aware method invocation. `x?.m()` invokes `m` only if `x` is not `null`.
+
 ### Core library changes
 
 * `dart:async`
diff --git a/DEPS b/DEPS
index 9f0e802..bb1cb58 100644
--- a/DEPS
+++ b/DEPS
@@ -49,7 +49,7 @@
   "collection_rev": "@1da9a07f32efa2ba0c391b289e2037391e31da0e",
   "crypto_rev" : "@2df57a1e26dd88e8d0614207d4b062c73209917d",
   "csslib_tag" : "@0.12.0",
-  "dartdoc_tag" : "@v0.5.0+3",
+  "dartdoc_rev" : "@23dbfa91819e3c6b72e635eb9cb64a0a3224ef84",
   "dart_services_rev" : "@7aea2574e6f3924bf409a80afb8ad52aa2be4f97",
   "dart_style_tag": "@0.2.0",
   "dev_compiler_rev": "@0.1.3",
@@ -196,7 +196,7 @@
   Var("dart_root") + "/third_party/pkg_tested/dart_style":
       (Var("github_mirror") % "dart_style") + Var("dart_style_tag"),
   Var("dart_root") + "/third_party/pkg/dartdoc":
-      (Var("github_mirror") % "dartdoc") + Var("dartdoc_tag"),
+      (Var("github_mirror") % "dartdoc") + Var("dartdoc_rev"),
   Var("dart_root") + "/third_party/pkg/dev_compiler":
       (Var("github_mirror") % "dev_compiler") + Var("dev_compiler_rev"),
   Var("dart_root") + "/third_party/pkg/glob":
diff --git a/pkg/analyzer/lib/src/generated/resolver.dart b/pkg/analyzer/lib/src/generated/resolver.dart
index 8110c8c..6792538 100644
--- a/pkg/analyzer/lib/src/generated/resolver.dart
+++ b/pkg/analyzer/lib/src/generated/resolver.dart
@@ -11227,7 +11227,11 @@
           return null;
         }
         DartType eventType = onDataParameters[0].type;
-        if (eventType.element == streamType.typeParameters[0]) {
+        // TODO(paulberry): checking that typeParameters.isNotEmpty is a
+        // band-aid fix for dartbug.com/24191.  Figure out what the correct
+        // logic should be.
+        if (streamType.typeParameters.isNotEmpty &&
+            eventType.element == streamType.typeParameters[0]) {
           return streamType.typeArguments[0];
         }
       }
diff --git a/pkg/analyzer/test/generated/non_error_resolver_test.dart b/pkg/analyzer/test/generated/non_error_resolver_test.dart
index 64da228..9b057a7 100644
--- a/pkg/analyzer/test/generated/non_error_resolver_test.dart
+++ b/pkg/analyzer/test/generated/non_error_resolver_test.dart
@@ -2898,6 +2898,22 @@
     verify([source]);
   }
 
+  void test_issue_24191() {
+    Source source = addSource('''
+import 'dart:async';
+
+class S extends Stream {}
+f(S s) async {
+  await for (var v in s) {
+    print(v);
+  }
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertNoErrors(source);
+    verify([source]);
+  }
+
   void test_listElementTypeNotAssignable() {
     Source source = addSource(r'''
 var v1 = <int> [42];
diff --git a/pkg/analyzer/test/generated/resolver_test.dart b/pkg/analyzer/test/generated/resolver_test.dart
index 4034068..5963b56 100644
--- a/pkg/analyzer/test/generated/resolver_test.dart
+++ b/pkg/analyzer/test/generated/resolver_test.dart
@@ -236,6 +236,9 @@
     // Stream
     ClassElementImpl streamElement =
         ElementFactory.classElement2("Stream", ["T"]);
+    streamElement.constructors = <ConstructorElement>[
+      ElementFactory.constructorElement2(streamElement, null)
+    ];
     DartType returnType = streamSubscriptionElement.type
         .substitute4(streamElement.type.typeArguments);
     List<DartType> parameterTypes = <DartType>[
diff --git a/pkg/compiler/lib/src/apiimpl.dart b/pkg/compiler/lib/src/apiimpl.dart
index 6c2f9c0..18b3ec3 100644
--- a/pkg/compiler/lib/src/apiimpl.dart
+++ b/pkg/compiler/lib/src/apiimpl.dart
@@ -389,7 +389,8 @@
         packages =
             new MapPackages(pkgs.parse(packageConfigContents, packageConfig));
       }).catchError((error) {
-        reportError(NO_LOCATION_SPANNABLE, MessageKind.INVALID_PACKAGE_CONFIG,
+        reportError(leg.NO_LOCATION_SPANNABLE,
+            leg.MessageKind.INVALID_PACKAGE_CONFIG,
             {'uri': packageConfig, 'exception': error});
         packages = Packages.noPackages;
       });
diff --git a/tools/VERSION b/tools/VERSION
index 79b12b13..0922b88 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -28,4 +28,4 @@
 MINOR 12
 PATCH 0
 PRERELEASE 5
-PRERELEASE_PATCH 9
+PRERELEASE_PATCH 10