diff --git a/src/checker.ts b/src/checker.ts
index 9fc55d4ca..df46bcd37 100644
--- a/src/checker.ts
+++ b/src/checker.ts
@@ -142,7 +142,6 @@ export class TypeChecker {
               node: arg,
             });
           }
-
         }
 
       }
@@ -159,7 +158,7 @@ export class TypeChecker {
     return this.getTypeOfNode(sym.declarations[0]);
   }
 
-  @memoize
+  @memoize(node => node.id)
   private getTypeOfNode(node: BoltSyntax): Type {
     switch (node.kind) {
       case SyntaxKind.BoltReferenceTypeExpression:
@@ -193,8 +192,8 @@ export class TypeChecker {
           type = this.resolveType('String', node)!;
         } else if (typeof node.value === 'boolean') {
           type = this.resolveType('bool', node)!;
-        } else if (typeof node.value === 'number') {
-          type = this.resolveType('int32', node)!;
+        } else if (typeof node.value === 'bigint') {
+          type = this.resolveType('i32', node)!;
         } else {
           throw new Error(`Could not derive type of constant expression.`);
         }
diff --git a/src/util.ts b/src/util.ts
index 939c278c9..9445eeea5 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -123,22 +123,26 @@ class DeepMap {
 
 }
 
-export function memoize(target: any, key: PropertyKey) {
-  const origMethod = target[key];
-  target[key] = function wrapper(...args: any[]) {
-    if (this.__MEMOIZE_CACHE === undefined) {
-      this.__MEMOIZE_CACHE = Object.create(null);
+export function memoize(hasher: (...args: any[]) => string) {
+  return function (target: any, key: PropertyKey) {
+    const origMethod = target[key];
+    target[key] = function wrapper(...args: any[]) {
+      if (this.__MEMOIZE_CACHE === undefined) {
+        this.__MEMOIZE_CACHE = Object.create(null);
+      }
+      if (this.__MEMOIZE_CACHE[key] === undefined) {
+        this.__MEMOIZE_CACHE[key] = Object.create(null);
+      }
+      const hashed = hasher(...args);
+      const cache = this.__MEMOIZE_CACHE[key];
+      if (hashed in cache) {
+        return cache[hashed];
+      }
+      const result = origMethod.apply(this, args);
+      cache[hashed] = result;
+      return result;
     }
-    if (this.__MEMOIZE_CACHE[key] === undefined) {
-      this.__MEMOIZE_CACHE[key] = new DeepMap();
-    }
-    const cache = this.__MEMOIZE_CACHE[key];
-    if (cache.has(args)) {
-      return cache.get(args);
-    }
-    const result = origMethod.apply(this, args);
-    cache.set(args, result);
-    return result;
+    return target;
   }
 }