diff --git a/core/src/nix/drv.sld b/core/src/nix/drv.sld
index bf0b814..b57f531 100644
--- a/core/src/nix/drv.sld
+++ b/core/src/nix/drv.sld
@@ -24,7 +24,7 @@
     drv-is-fod
 
     derivation-serialize derivation-path-references derivation-path derivation-read read-drv-path
-    make-fixed-output-derivation make-input-addressed-derivation make-impure-derivation make-ca-derivation
+    make-fixed-output-derivation make-input-addressed-derivation make-ca-derivation
     modulo-hash-drv-contents)
 
   (begin
@@ -58,7 +58,7 @@
         (derivation-output-recursive drvout)))
 
     (define (derivation-output-placeholder? drvout)
-      (member (derivation-output-hash drvout) '(floating impure)))
+      (member (derivation-output-hash drvout) '(floating)))
 
     (define (derivation-output-path-length drv output-name)
       ; /nix/store/a0a3n97c93ckfg3a920aqnycxdznbbmi-module-output
@@ -179,9 +179,6 @@
       (define first-output-is-hash (bytevector? (derivation-output-hash (cdr first-output))))
       (and (= (length outs) 1) (string=? first-output-id "out") first-output-is-hash))
 
-    (define (drv-is-impure drv)
-      (eq? (derivation-output-hash (cdr (car (derivation-outputs drv)))) 'impure))
-
     (define (env-pair< left right)
       (string<? (car left) (car right)))
 
@@ -191,8 +188,6 @@
         ((drv-is-fod drv)
          (let ((out (cdar (derivation-outputs drv))))
           (string->utf8 (string-append "fixed:out:" (if (derivation-output-recursive out) "r:" "") (derivation-output-algo out) ":" (hex (derivation-output-hash out)) ":" (derivation-output-path out)))))
-        ((drv-is-impure drv)
-         (string->utf8 "impure"))
         (else
          (let ((remapped-input-drvs '())
                (output-port (open-output-bytevector))
@@ -200,7 +195,7 @@
              ; TODO: this needs to merge output names too (depending on two distinct drvs with the same output hash requires merging their output names.)
              (for-each (lambda (l)
                         (let* ((new-hash (hex (modulo-hash-drv (car l)))))
-                              (set! is-deferred (or is-deferred (derivation-metadata-is-deferred (derivation-metadata (car l))) (drv-is-impure (car l))))
+                              (set! is-deferred (or is-deferred (derivation-metadata-is-deferred (derivation-metadata (car l)))))
                               (unless (assoc new-hash remapped-input-drvs) (set! remapped-input-drvs (cons (cons new-hash (cdr l)) remapped-input-drvs)))))
                        (derivation-input-drvs drv))
              (set! remapped-input-drvs (list-sort env-pair< remapped-input-drvs))
@@ -274,19 +269,6 @@
       (sanity-check-drv drv)
       drv)
 
-    ;; Creates an impure addressed derivation with specified parameters.
-    (define (make-impure-derivation name platform input-drvs input-srcs builder nenv noutputs)
-      (define compat-env (if (%derivation-compatible) `(("name" . ,name) ("builder" . ,(car builder)) ("system" . ,platform)) '()))
-
-      (define outputs (list-sort env-pair< (map (lambda (l) (cons l (make-derivation-output
-                                                                     #f 'impure "sha256" #t))) noutputs)))
-      (define env (list-sort env-pair< (filter-environment env (append compat-env (map (lambda (l) (cons (car l) (make-placeholder (car l)))) outputs)))))
-
-      (define drv (make-derivation name outputs input-drvs input-srcs platform (car builder) (cdr builder) env (make-derivation-metadata #f #f #t #f #f)))
-      (define pathhash (string-copy (derivation-path drv) (+ 1 (string-length (%store-dir))) (+ 33 (string-length (%store-dir)))))
-      (for-each (lambda (pair) (set-derivation-output-path! (cdr pair) (make-upstream-output-placeholder pathhash name (car pair)))) (derivation-outputs drv))
-      drv)
-
     ;; Creates a content-addressed derivation with specified parameters.
     (define (make-ca-derivation name platform input-drvs input-srcs builder nenv noutputs)
       (define compat-env (if (%derivation-compatible) `(("name" . ,name) ("builder" . ,(car builder)) ("system" . ,platform)) '()))
@@ -305,11 +287,10 @@
       (define output (cdr pair))
       (write-paren-list write-quoted-string
         (list output-name
-          (if (member (derivation-output-hash output) '(impure floating)) "" (or (derivation-output-path output) ""))
+          (if (member (derivation-output-hash output) '(floating)) "" (or (derivation-output-path output) ""))
           (string-append (if (derivation-output-recursive output) "r:" "") (or (derivation-output-algo output) ""))
           (cond
             ((bytevector? (derivation-output-hash output)) (hex (derivation-output-hash output)))
-            ((eq? (derivation-output-hash output) 'impure) "impure")
             ((eq? (derivation-output-hash output) 'floating) "")
             ((not (derivation-output-hash output)) "")
             (else (error "unknown derivation output hash type"))))))