diff --git a/src/interpreter/instructions/mod.rs b/src/interpreter/instructions/mod.rs
index 909d886..9882532 100644
--- a/src/interpreter/instructions/mod.rs
+++ b/src/interpreter/instructions/mod.rs
@@ -222,10 +222,10 @@ where
     MemoryView: wasm::structures::MemoryView,
     Instance: wasm::structures::Instance<Export, LocalImport, Memory, MemoryView>,
 {
-    let func_inputs = local_import.inputs();
+    let func_inputs = local_import.arguments();
 
     for (func_input_arg, value) in func_inputs.iter().zip(values.iter()) {
-        is_value_compatible_to_type(instance, &func_input_arg, value, instruction)?;
+        is_value_compatible_to_type(instance, &func_input_arg.ty, value, instruction)?;
     }
 
     Ok(())
@@ -363,7 +363,7 @@ pub(crate) mod tests {
             self.outputs.len()
         }
 
-        fn inputs(&self) -> &[InterfaceType] {
+        fn arguments(&self) -> &[InterfaceType] {
             &self.inputs
         }
 
@@ -391,7 +391,7 @@ pub(crate) mod tests {
             self.outputs.len()
         }
 
-        fn inputs(&self) -> &[InterfaceType] {
+        fn arguments(&self) -> &[InterfaceType] {
             &self.inputs
         }
 
diff --git a/src/interpreter/wasm/structures.rs b/src/interpreter/wasm/structures.rs
index d3be40e..66b1985 100644
--- a/src/interpreter/wasm/structures.rs
+++ b/src/interpreter/wasm/structures.rs
@@ -3,6 +3,7 @@
 use crate::types::RecordType;
 use crate::{types::InterfaceType, values::InterfaceValue};
 use std::{cell::Cell, ops::Deref};
+use crate::ast::FunctionArg;
 
 pub trait TypedIndex: Copy + Clone {
     fn new(index: usize) -> Self;
@@ -43,7 +44,7 @@ impl LocalImportIndex for FunctionIndex {
 pub trait Export {
     fn inputs_cardinality(&self) -> usize;
     fn outputs_cardinality(&self) -> usize;
-    fn inputs(&self) -> &[InterfaceType];
+    fn arguments(&self) -> &[FunctionArg];
     fn outputs(&self) -> &[InterfaceType];
     fn call(&self, arguments: &[InterfaceValue]) -> Result<Vec<InterfaceValue>, ()>;
 }
@@ -51,7 +52,7 @@ pub trait Export {
 pub trait LocalImport {
     fn inputs_cardinality(&self) -> usize;
     fn outputs_cardinality(&self) -> usize;
-    fn inputs(&self) -> &[InterfaceType];
+    fn arguments(&self) -> &[FunctionArg];
     fn outputs(&self) -> &[InterfaceType];
     fn call(&self, arguments: &[InterfaceValue]) -> Result<Vec<InterfaceValue>, ()>;
 }
@@ -88,7 +89,7 @@ impl Export for () {
         0
     }
 
-    fn inputs(&self) -> &[InterfaceType] {
+    fn arguments(&self) -> &[FunctionArg] {
         &[]
     }
 
@@ -110,7 +111,7 @@ impl LocalImport for () {
         0
     }
 
-    fn inputs(&self) -> &[InterfaceType] {
+    fn arguments(&self) -> &[FunctionArg] {
         &[]
     }
 
diff --git a/src/types.rs b/src/types.rs
index 444667d..6317487 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -4,7 +4,7 @@ use crate::vec1::Vec1;
 use serde::{Deserialize, Serialize};
 
 /// Represents the types supported by WIT.
-#[derive(PartialEq, Debug, Clone, Serialize, Deserialize)]
+#[derive(PartialEq, Eq, Debug, Clone, Serialize, Deserialize)]
 pub enum InterfaceType {
     /// A 8-bits signed integer.
     S8,
@@ -57,7 +57,7 @@ pub enum InterfaceType {
 }
 
 /// Represents a record field type.
-#[derive(PartialEq, Debug, Clone, Serialize, Deserialize)]
+#[derive(PartialEq, Eq, Debug, Clone, Serialize, Deserialize)]
 pub struct RecordFieldType {
     // TODO: make name optional to support structures with anonymous fields in Rust
     /// A field name.