diff --git a/fine/src/semantics.rs b/fine/src/semantics.rs
index 57a74823..455ab09d 100644
--- a/fine/src/semantics.rs
+++ b/fine/src/semantics.rs
@@ -79,8 +79,6 @@ pub enum Type {
     String,
     Bool,
 
-    TypeArgument(TreeRef, Box<str>), // An un-bound type argument
-
     Function(Vec<Box<Type>>, Box<Type>),
 }
 
@@ -105,19 +103,9 @@ impl Type {
             (Type::Error, _) => true,
             (_, Type::Error) => true,
 
-            (Type::TypeArgument(a_id, ..), Type::TypeArgument(b_id, ..)) => a_id == b_id,
-
             (_, _) => false,
         }
     }
-
-    pub fn is_generic(&self) -> bool {
-        match self {
-            Type::TypeArgument(..) => true,
-            Type::Function(a, b) => a.iter().any(|t| t.is_generic()) || b.is_generic(),
-            _ => false,
-        }
-    }
 }
 
 impl fmt::Debug for Type {
@@ -137,7 +125,6 @@ impl fmt::Display for Type {
             String => write!(f, "string"),
             Bool => write!(f, "bool"),
             MagicPrintGarbage => write!(f, "MagicPrintGarbage"),
-            TypeArgument(_, id) => write!(f, "{id}"),
             Function(args, ret) => {
                 write!(f, "fun (")?;
                 let mut first = true;
@@ -666,7 +653,7 @@ impl<'a> Semantics<'a> {
 
             TreeKind::FunctionDecl => self.type_of_function_decl(tree),
             TreeKind::ReturnType => self.type_of_return_type(tree),
-            TreeKind::Parameter => self.type_of_parameter(t, tree),
+            TreeKind::Parameter => self.type_of_parameter(tree),
 
             _ => self.internal_compiler_error(Some(t), "asking for a nonsense type"),
         };
@@ -1027,14 +1014,13 @@ impl<'a> Semantics<'a> {
         Some(Type::Function(parameter_types, return_type))
     }
 
-    fn type_of_parameter(&self, t: TreeRef, tree: &Tree) -> Option<Type> {
+    fn type_of_parameter(&self, tree: &Tree) -> Option<Type> {
         assert_eq!(tree.kind, TreeKind::Parameter);
         match tree.child_of_kind(self.syntax_tree, TreeKind::TypeExpression) {
             Some(t) => Some(self.type_of(t)),
             None => {
-                // It must be a generic parameter! We'll name this one after the tree where it exists.
-                let name = tree.nth_token(0)?;
-                Some(Type::TypeArgument(t, format!("${}", name.as_str()).into()))
+                self.report_error_tree(tree, format!("the parameter is missing a type"));
+                Some(Type::Error)
             }
         }
     }
@@ -1126,7 +1112,7 @@ pub fn check(s: &Semantics) {
             TreeKind::File => {}
             TreeKind::FunctionDecl => check_function_decl(s, t, tree),
             TreeKind::ParamList => {}
-            TreeKind::Parameter => {}
+            TreeKind::Parameter => check_parameter(s, t),
             TreeKind::TypeExpression => {
                 let _ = s.type_of_type_expr(tree);
             }
@@ -1234,6 +1220,10 @@ fn check_return_statement(s: &Semantics, tree: &Tree) {
     // OK this one is a little bit messed up because it reaches *up*, sorry.
 }
 
+fn check_parameter(s: &Semantics, t: TreeRef) {
+    let _ = s.type_of(t);
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/fine/tests/expression/errors/missing_parameter.fine b/fine/tests/expression/errors/missing_parameter.fine
new file mode 100644
index 00000000..9bd2ae3e
--- /dev/null
+++ b/fine/tests/expression/errors/missing_parameter.fine
@@ -0,0 +1,5 @@
+fun this_is_missing_a_type(x) -> f64 {
+  23
+}
+
+// @check-error: the parameter is missing a type
\ No newline at end of file