diff --git a/compiler/src/expression/expression.rs b/compiler/src/expression/expression.rs
index 0db31dd5bb..1afdd6bc43 100644
--- a/compiler/src/expression/expression.rs
+++ b/compiler/src/expression/expression.rs
@@ -55,52 +55,6 @@ impl<F: Field + PrimeField, G: GroupType<F>> ConstrainedProgram<F, G> {
         Ok(result_value)
     }
 
-    fn enforce_function_call_expression<CS: ConstraintSystem<F>>(
-        &mut self,
-        cs: &mut CS,
-        file_scope: String,
-        function_scope: String,
-        expected_types: &Vec<Type>,
-        function: Box<Expression>,
-        arguments: Vec<Expression>,
-        span: Span,
-    ) -> Result<ConstrainedValue<F, G>, ExpressionError> {
-        let function_value = self.enforce_expression(
-            cs,
-            file_scope.clone(),
-            function_scope.clone(),
-            expected_types,
-            *function.clone(),
-        )?;
-
-        let (outer_scope, function_call) = function_value.extract_function(file_scope.clone(), span.clone())?;
-
-        let name_unique = format!(
-            "function call {} {}:{}",
-            function_call.get_name(),
-            span.line,
-            span.start,
-        );
-
-        match self.enforce_function(
-            &mut cs.ns(|| name_unique),
-            outer_scope,
-            function_scope,
-            function_call,
-            arguments,
-        ) {
-            Ok(ConstrainedValue::Return(return_values)) => {
-                if return_values.len() == 1 {
-                    Ok(return_values[0].clone())
-                } else {
-                    Ok(ConstrainedValue::Return(return_values))
-                }
-            }
-            Ok(_) => Err(ExpressionError::function_no_return(function.to_string(), span)),
-            Err(error) => Err(ExpressionError::from(Box::new(error))),
-        }
-    }
-
     pub(crate) fn enforce_number_implicit(
         expected_types: &Vec<Type>,
         value: String,
diff --git a/compiler/src/expression/function/function.rs b/compiler/src/expression/function/function.rs
new file mode 100644
index 0000000000..266f935110
--- /dev/null
+++ b/compiler/src/expression/function/function.rs
@@ -0,0 +1,57 @@
+//! Methods to enforce constraints on expressions in a compiled Leo program.
+
+use crate::{errors::ExpressionError, program::ConstrainedProgram, value::ConstrainedValue, GroupType};
+use leo_types::{Expression, Span, Type};
+
+use snarkos_models::{
+    curves::{Field, PrimeField},
+    gadgets::r1cs::ConstraintSystem,
+};
+
+impl<F: Field + PrimeField, G: GroupType<F>> ConstrainedProgram<F, G> {
+    pub fn enforce_function_call_expression<CS: ConstraintSystem<F>>(
+        &mut self,
+        cs: &mut CS,
+        file_scope: String,
+        function_scope: String,
+        expected_types: &Vec<Type>,
+        function: Box<Expression>,
+        arguments: Vec<Expression>,
+        span: Span,
+    ) -> Result<ConstrainedValue<F, G>, ExpressionError> {
+        let function_value = self.enforce_expression(
+            cs,
+            file_scope.clone(),
+            function_scope.clone(),
+            expected_types,
+            *function.clone(),
+        )?;
+
+        let (outer_scope, function_call) = function_value.extract_function(file_scope.clone(), span.clone())?;
+
+        let name_unique = format!(
+            "function call {} {}:{}",
+            function_call.get_name(),
+            span.line,
+            span.start,
+        );
+
+        match self.enforce_function(
+            &mut cs.ns(|| name_unique),
+            outer_scope,
+            function_scope,
+            function_call,
+            arguments,
+        ) {
+            Ok(ConstrainedValue::Return(return_values)) => {
+                if return_values.len() == 1 {
+                    Ok(return_values[0].clone())
+                } else {
+                    Ok(ConstrainedValue::Return(return_values))
+                }
+            }
+            Ok(_) => Err(ExpressionError::function_no_return(function.to_string(), span)),
+            Err(error) => Err(ExpressionError::from(Box::new(error))),
+        }
+    }
+}
diff --git a/compiler/src/expression/function/mod.rs b/compiler/src/expression/function/mod.rs
new file mode 100644
index 0000000000..80945cf378
--- /dev/null
+++ b/compiler/src/expression/function/mod.rs
@@ -0,0 +1,2 @@
+pub mod function;
+pub use self::function::*;
diff --git a/compiler/src/expression/mod.rs b/compiler/src/expression/mod.rs
index f83eaa3b05..471c140aeb 100644
--- a/compiler/src/expression/mod.rs
+++ b/compiler/src/expression/mod.rs
@@ -15,6 +15,9 @@ pub use self::conditional::*;
 pub mod expression;
 pub use self::expression::*;
 
+pub mod function;
+pub use self::function::*;
+
 pub mod logical;
 pub use self::logical::*;