diff --git a/core/src/magic.sld b/core/src/magic.sld
index 53d8b37..e5de45b 100644
--- a/core/src/magic.sld
+++ b/core/src/magic.sld
@@ -20,7 +20,7 @@
 
     store-path-path store-path-build store-path-materialize store-path-realisation
     store-path-for-text store-path-for-fod store-path-for-drv
-    store-path-for-impure-drv store-path-for-ca-drv store-path-for-ca-drv*
+    store-path-for-ca-drv store-path-for-ca-drv*
     store-path-realised store-path-open
     store-path-devirtualise
 
@@ -187,17 +187,6 @@
      (define drv (make-input-addressed-derivation name platform input-drvs input-srcs (zexp-evaluation-value collected-builder) (zexp-evaluation-value collected-env) outputs))
      (map (lambda (l) (cons (car l) (make-store-path drv (car l) #f))) (derivation-outputs drv)))
 
-   ;; Returns an alist of output -> `<store-path>` for an impure derivation.
-   (define (store-path-for-impure-drv name platform builder env outputs)
-     (increment-counter 0)
-     (define collected-env (zexp-unwrap env))
-     (define collected-builder (zexp-unwrap builder))
-
-     (define input-drvs (merge-drvs (zexp-evaluation-drvs collected-env) (zexp-evaluation-drvs collected-builder)))
-     (define input-srcs (merge-srcs (zexp-evaluation-srcs collected-env) (zexp-evaluation-srcs collected-builder)))
-     (define drv (make-impure-derivation name platform input-drvs input-srcs (zexp-evaluation-value collected-builder) (zexp-evaluation-value collected-env) outputs))
-     (map (lambda (l) (cons (car l) (make-store-path drv (car l) #f))) (derivation-outputs drv)))
-
    ;; Returns an alist of output -> `<store-path>` for a content-addressed derivation.
    (define (store-path-for-ca-drv name platform builder env outputs)
      (increment-counter 0)