Minor type inference fixes to do with null and bottom types.

pkg/front_end/testcases/inference/block_bodied_lambdas_returns.dart

Index: pkg/front_end/testcases/inference/block_bodied_lambdas_returns.dart
diff --git a/pkg/front_end/testcases/inference/block_bodied_lambdas_returns.dart b/pkg/front_end/testcases/inference/block_bodied_lambdas_returns.dart
new file mode 100644
index 0000000000000000000000000000000000000000..852fb3fd716c2b84e6e45fdd97deef4c17f51301
--- /dev/null
+++ b/pkg/front_end/testcases/inference/block_bodied_lambdas_returns.dart
@@ -0,0 +1,82 @@
+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/*@testedFeatures=inference*/
+library test;
+
+main() {
+  var /*@type=() -> Null*/ a = /*@returnType=Null*/ () {};
+  var /*@type=() -> Null*/ b = /*@returnType=Null*/ () {
+    return;
+  };
+  var /*@type=() -> Null*/ c = /*@returnType=Null*/ () {
+    return null;
+  };
+  var /*@type=() -> int*/ d = /*@returnType=int*/ () {
+    return 0;
+  };
+  var /*@type=(bool) -> Null*/ e = /*@returnType=Null*/ (bool b) {
+    if (b) {
+      return;
+    } else {
+      return;
+    }
+  };
+  var /*@type=(bool) -> Null*/ f = /*@returnType=Null*/ (bool b) {
+    if (b) {
+      return;
+    } else {
+      return null;
+    }
+  };
+  var /*@type=(bool) -> int*/ g = /*@returnType=int*/ (bool b) {
+    if (b) {
+      return;
+    } else {
+      return 0;
+    }
+  };
+  var /*@type=(bool) -> Null*/ h = /*@returnType=Null*/ (bool b) {
+    if (b) {
+      return null;
+    } else {
+      return;
+    }
+  };
+  var /*@type=(bool) -> Null*/ i = /*@returnType=Null*/ (bool b) {
+    if (b) {
+      return null;
+    } else {
+      return null;
+    }
+  };
+  var /*@type=(bool) -> int*/ j = /*@returnType=int*/ (bool b) {
+    if (b) {
+      return null;
+    } else {
+      return 0;
+    }
+  };
+  var /*@type=(bool) -> int*/ k = /*@returnType=int*/ (bool b) {
+    if (b) {
+      return 0;
+    } else {
+      return;
+    }
+  };
+  var /*@type=(bool) -> int*/ l = /*@returnType=int*/ (bool b) {
+    if (b) {
+      return 0;
+    } else {
+      return null;
+    }
+  };
+  var /*@type=(bool) -> int*/ m = /*@returnType=int*/ (bool b) {
+    if (b) {
+      return 0;
+    } else {
+      return 0;
+    }
+  };
+}