diff --git a/index.d.ts b/index.d.ts
index d6192d9..1d1808b 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -177,7 +177,7 @@ export function apply(input: any): any;
 
 export function assignFn(funType: any, paramType: any): any;
 
-export function assignFnSubstitutions(funType: any, paramType: any): [any, any];
+export function assignFnSubstitutions(funType: any, paramType: any, skip: number): [any, any, any, any];
 
 export function capitalizeFirstLetter(val: any): any;
 
diff --git a/lib/generics/generics.js b/lib/generics/generics.js
index 10733c2..eed5c41 100644
--- a/lib/generics/generics.js
+++ b/lib/generics/generics.js
@@ -189,22 +189,24 @@ export const substitute = (type, substitutions, stack=[]) => {
 };
 
 export const assignFn = (funType, paramType) => {
-  return assignFnSubstitutions(funType, paramType)[2];
+  const [inType, inSubst, outType, outSubst] = assignFnSubstitutions(funType, paramType);
+  // return recomputeTypeVars([outType])[0];
+  return outType;
 };
 
 // same as above, but also returns the substitutions that took place
-export const assignFnSubstitutions = (funType, paramType) => {
+export const assignFnSubstitutions = (funType, paramType, skip=0) => {
   if (getSymbol(funType) !== symbolFunction) {
     throw new NotAFunctionError(`${prettyT(funType)} is not a function type!`);
   }
-  const [[refunType, funS], [reparamType, paramS]] = recomputeTypeVarsSubstitutions([funType, paramType]);
-  const recomputationSubstitutions = mergeTwoWay(funS, paramS);
+  const [[refunType, funS], [reparamType, paramS]] = recomputeTypeVarsSubstitutions([funType, paramType], skip);
   const [inType, outType] = refunType.params.map(p => p(refunType));
   const {type: newInType, substitutions} = __unify(inType, reparamType);
-  const inTypeSubst = mergeTwoWay(substitutions, recomputationSubstitutions);
-  const substitutedFnType = substitute(outType, substitutions);
-  const [computedOutType, outSubst] = recomputeTypeVarsSubstitutions([substitutedFnType])[0];
-  return [newInType, inTypeSubst, computedOutType, outSubst];
+  const totalParamSubstitutions = mergeTwoWay(substitutions, paramS);
+  const newOutType = substitute(outType, substitutions);
+  const [[finalOutType, outsubst]] = recomputeTypeVarsSubstitutions([newOutType], skip);
+  const totalOutSubstitutions = mergeTwoWay(funS, outsubst);
+  return [newInType, totalParamSubstitutions, finalOutType, totalOutSubstitutions];
 };
 
 // Ensures that no type variables overlap
@@ -213,8 +215,8 @@ export const recomputeTypeVars = types => {
     .map(([newType, _subst]) => newType);
 };
 
-export const recomputeTypeVarsSubstitutions = types => {
-  let nextIdx = 0;
+export const recomputeTypeVarsSubstitutions = (types, skip=0) => {
+  let nextIdx = skip;
   return types.map(type => {
     const substitutions = new Map();
     const typeVars = occurring(type);