diff --git a/src/protocol/parser/pass_typing.rs b/src/protocol/parser/pass_typing.rs
index ae7deef1ad37d8cf8df685096040dbdb22e4678c..46b17c2d98ac567766dd264cc04bf251aa068be1 100644
--- a/src/protocol/parser/pass_typing.rs
+++ b/src/protocol/parser/pass_typing.rs
@@ -3534,7 +3534,10 @@ impl PassTyping {
         for concrete_part in concrete_type {
             match concrete_part {
                 CTP::Void => parser_type.push(ITP::Void),
-                CTP::Message => parser_type.push(ITP::Message),
+                CTP::Message => {
+                    parser_type.push(ITP::Message);
+                    parser_type.push(ITP::UInt8)
+                },
                 CTP::Bool => parser_type.push(ITP::Bool),
                 CTP::UInt8 => parser_type.push(ITP::UInt8),
                 CTP::UInt16 => parser_type.push(ITP::UInt16),
diff --git a/src/protocol/parser/type_table.rs b/src/protocol/parser/type_table.rs
index 9c1ffedd4fa3fe53c89b1f5770836019e83b8696..6acf92b60bc3cebb569418508f605236a7255dde 100644
--- a/src/protocol/parser/type_table.rs
+++ b/src/protocol/parser/type_table.rs
@@ -927,7 +927,7 @@ impl TypeTable {
 
     /// Builds base component type.
     fn build_base_component_definition(&mut self, modules: &[Module], ctx: &mut PassCtx, definition_id: DefinitionId) -> Result<(), ParseError> {
-        debug_assert!(self.lookup.contains_key(&definition_id), "base component already built");
+        debug_assert!(!self.lookup.contains_key(&definition_id), "base component already built");
 
         let definition = &ctx.heap[definition_id].as_component();
         let root_id = definition.defined_in;
diff --git a/src/protocol/tests/eval_silly.rs b/src/protocol/tests/eval_silly.rs
index 62cb0ca3ae138c85373515dfe4c54f0428c30b3d..db7203cd559ffd171bf75c785788e4da7ecc27e4 100644
--- a/src/protocol/tests/eval_silly.rs
+++ b/src/protocol/tests/eval_silly.rs
@@ -135,14 +135,14 @@ fn test_slicing_magic() {
         f.call_ok(Some(Value::Bool(true)));
     }).for_struct("Holder", |s| { s
         .assert_num_monomorphs(8)
-        .assert_has_monomorph("u8")
-        .assert_has_monomorph("u16")
-        .assert_has_monomorph("u32")
-        .assert_has_monomorph("u64")
-        .assert_has_monomorph("s8")
-        .assert_has_monomorph("s16")
-        .assert_has_monomorph("s32")
-        .assert_has_monomorph("s64");
+        .assert_has_monomorph("Holder<u8>")
+        .assert_has_monomorph("Holder<u16>")
+        .assert_has_monomorph("Holder<u32>")
+        .assert_has_monomorph("Holder<u64>")
+        .assert_has_monomorph("Holder<s8>")
+        .assert_has_monomorph("Holder<s16>")
+        .assert_has_monomorph("Holder<s32>")
+        .assert_has_monomorph("Holder<s64>");
     });
 }