fix issue 1110 (handle void better)

frog/parser.dart

Index: frog/parser.dart
diff --git a/frog/parser.dart b/frog/parser.dart
index 294d3d20458d6d9b29723f15127f722976c0e142..2c3e0f49ce3d85cbf742c3ccbe0e1a61f52e237e 100644
--- a/frog/parser.dart
+++ b/frog/parser.dart
@@ -1251,6 +1251,10 @@ class Parser {
   }
 
   _typeAsIdentifier(type) {
+    if (type.name.name == 'void') {
+      _errorExpected('identifer, but found "${type.name.name}"');
+    }
+
     // TODO(jimhug): lots of errors to check for
     return type.name;
   }
@@ -1655,6 +1659,9 @@ class Parser {
     } else if (expr is DeclaredIdentifier) {
       name = expr.name;
       type = expr.type;
+      if (name == null) {
+        _error('expected name and type', expr.span);
+      }
     } else {
       _error('bad function body', expr.span);
     }