Compiler: error on enum without members. Fixes #3447

Ary Borenszweig · Ary Borenszweig · commit f980578fffcf · 2016-12-07T09:34:37.000-03:00
diff --git a/spec/compiler/semantic/enum_spec.cr b/spec/compiler/semantic/enum_spec.cr
@@ -298,4 +298,12 @@ describe "Semantic: enum" do
       ),
       "can't inherit Enum. Use the enum keyword to define enums"
   end
+
+  it "errors on enum without members (#3447)" do
+    assert_error %(
+      enum Foo
+      end
+      ),
+      "enum Foo must have at least one member"
+  end
 end
diff --git a/src/compiler/crystal/semantic/top_level_visitor.cr b/src/compiler/crystal/semantic/top_level_visitor.cr
@@ -485,6 +485,10 @@ class Crystal::TopLevelVisitor < Crystal::SemanticVisitor
         is_flags: is_flags)
     end
 
+    if enum_type.types.empty?
+      node.raise "enum #{node.name} must have at least one member"
+    end
+
     unless existed
       if is_flags
         unless enum_type.types["None"]?
