diff --git a/symbol-table/src/types/functions/function.rs b/symbol-table/src/types/functions/function.rs
index ffc35fde98..3c84176fdc 100644
--- a/symbol-table/src/types/functions/function.rs
+++ b/symbol-table/src/types/functions/function.rs
@@ -127,7 +127,9 @@ impl FunctionType {
     pub fn num_inputs(&self) -> usize {
         self.inputs
             .iter()
-            .fold(0, |acc, function_input| acc + function_input.count())
+            .filter(|function_input| !function_input.is_self())
+            .count()
+        // .fold(0, |acc, function_input| acc + function_input.arguments())
     }
 
     ///
@@ -139,13 +141,10 @@ impl FunctionType {
     }
 
     ///
-    /// Returns a vector of [&FunctionInputType] removing `self` and `mut self` inputs.
+    /// Returns an iterator of [&FunctionInputType] removing `self` and `mut self` inputs.
     ///
-    pub fn filter_self_inputs(&self) -> Vec<&FunctionInputType> {
-        self.inputs
-            .iter()
-            .filter(|input| !input.is_self())
-            .collect::<Vec<&FunctionInputType>>()
+    pub fn filter_self_inputs(&self) -> impl Iterator<Item = &FunctionInputType> {
+        self.inputs.iter().filter(|input| !input.is_self())
     }
 }
 
diff --git a/symbol-table/src/types/functions/function_input.rs b/symbol-table/src/types/functions/function_input.rs
index 66a8180f98..cee5ed1df5 100644
--- a/symbol-table/src/types/functions/function_input.rs
+++ b/symbol-table/src/types/functions/function_input.rs
@@ -77,15 +77,6 @@ impl FunctionInputType {
         }
     }
 
-    ///
-    /// Returns `0` if the function input is a `self` or `mut self` keyword which does not have to
-    /// provided in a call to the function.
-    /// Returns `1` if a variable must be provided in a call to the function.
-    ///
-    pub fn count(&self) -> usize {
-        if self.is_self() { 0 } else { 1 }
-    }
-
     ///
     /// Return a new `FunctionInputType` from a given `FunctionInput`.
     ///
diff --git a/type-inference/src/objects/frame.rs b/type-inference/src/objects/frame.rs
index e725bff39b..20b1c44612 100644
--- a/type-inference/src/objects/frame.rs
+++ b/type-inference/src/objects/frame.rs
@@ -1120,10 +1120,8 @@ impl Frame {
         }
 
         // Filter out `self` and `mut self` keywords.
-        let expected_inputs = function_type.filter_self_inputs();
-
         // Assert function inputs are correct types.
-        for (expected_input, actual_input) in expected_inputs.iter().zip(inputs) {
+        for (expected_input, actual_input) in function_type.filter_self_inputs().zip(inputs) {
             // Parse expected input type.
             let expected_type = expected_input.type_();