diff --git a/packages/core/pattern.mjs b/packages/core/pattern.mjs
index a86290fd..649723a5 100644
--- a/packages/core/pattern.mjs
+++ b/packages/core/pattern.mjs
@@ -451,7 +451,9 @@ export class Pattern {
    * @noAutocomplete
    */
   withHaps(func) {
-    return new Pattern((state) => func(this.query(state), state));
+    const result = new Pattern((state) => func(this.query(state), state));
+    result.weight = this.weight;
+    return result;
   }
 
   /**
@@ -484,6 +486,7 @@ export class Pattern {
     const result = this.withHap((hap) => hap.setContext(func(hap.context)));
     if (this.__pure !== undefined) {
       result.__pure = this.__pure;
+      result.__pure_loc = this.__pure_loc;
     }
     return result;
   }
@@ -510,10 +513,15 @@ export class Pattern {
       start,
       end,
     };
-    return this.withContext((context) => {
+    const result = this.withContext((context) => {
       const locations = (context.locations || []).concat([location]);
       return { ...context, locations };
     });
+    if (this.__pure) {
+      result.__pure = this.__pure;
+      result.__pure_loc = location;
+    }
+    return result;
   }
 
   /**
@@ -1608,7 +1616,12 @@ export function register(name, func, patternify = true, preserveWeight = false)
 
         if (firstArgs.every((arg) => arg.__pure != undefined)) {
           const pureArgs = firstArgs.map((arg) => arg.__pure);
+          const pureLocs = firstArgs.filter((arg) => arg.__pure_loc).map((arg) => arg.__pure_loc);
           result = func(...pureArgs, pat);
+          result = result.withContext((context) => {
+            const locations = (context.locations || []).concat(pureLocs);
+            return { ...context, locations };
+          });
         } else {
           const [left, ...right] = firstArgs;