From 002033281031e63444dc8d30586bd6c3b4163635 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Thu, 21 Mar 2019 18:12:49 -0600
Subject: [PATCH] raco demod: discard unusable macro implementations

Prune away "phase -1" macro registrations, because they're useless,
and because the expander's evaluation of linklets now actively rejects
them.
---
 .../compiler/demodularizer/gc.rkt             | 14 ++++++++++---
 .../compiler/demodularizer/merge.rkt          | 20 ++++++++++++++-----
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/pkgs/compiler-lib/compiler/demodularizer/gc.rkt b/pkgs/compiler-lib/compiler/demodularizer/gc.rkt
index a2c1fad191..fd90353235 100644
--- a/pkgs/compiler-lib/compiler/demodularizer/gc.rkt
+++ b/pkgs/compiler-lib/compiler/demodularizer/gc.rkt
@@ -92,7 +92,14 @@
       [(closure code gen-id) #t]
       [(inline-variant direct inline) #t]
       [(case-lam name clauses) #t]
-      [_ (lam? b)]))
+      [(let-one rhs body type unused?)
+       (and (pure? rhs)
+            (pure? body))]
+      [(seq forms)
+       (for/and ([form (in-list forms)])
+         (pure? form))]
+      [_ (or (lam? b)
+             (void? b))]))
 
   (for ([b (in-list body)])
     (match b
@@ -114,7 +121,8 @@
        (unless (or assume-pure?
                    (pure? rhs))
          (used-rhs!))]
-      [_ (used! b)]))
+      [_ (unless (pure? b)
+           (used! b))]))
   
   ;; Anything not marked as used at this point can be dropped
   (define new-internals
@@ -152,7 +160,7 @@
                         [(def-values ids rhs)
                          (for/or ([id (in-list ids)])
                            (eq? 'used (hash-ref used (toplevel-pos id) #f)))]
-                        [else (not (void? b))]))
+                        [else (not (pure? b))]))
       b))
 
   (define new-body (remap-positions used-body
diff --git a/pkgs/compiler-lib/compiler/demodularizer/merge.rkt b/pkgs/compiler-lib/compiler/demodularizer/merge.rkt
index 4502defb09..ef14f1688a 100644
--- a/pkgs/compiler-lib/compiler/demodularizer/merge.rkt
+++ b/pkgs/compiler-lib/compiler/demodularizer/merge.rkt
@@ -120,15 +120,25 @@
                         #:application-hook
                         (lambda (rator rands remap)
                           ;; Check for a `(.get-syntax-literal! '<pos>)` call
+                          ;; or a `(.set-transformer! '<sym> <expr>)` call
                           (cond
                             [(and (toplevel? rator)
                                   (let ([i (hash-ref pos-to-name/import (toplevel-pos rator))])
                                     (and (import? i)
-                                         (eqv? syntax-literals-pos (import-pos i)))))
-                             ;; This is a `(.get-syntax-literal! '<pos>)` call
-                             (application (remap rator)
-                                          ;; To support syntax objects, change the offset
-                                          rands)]
+                                         i)))
+                             => (lambda (i)
+                                  (cond
+                                    [(and any-syntax-literals?
+                                          (eqv? syntax-literals-pos (import-pos i)))
+                                     ;; This is a `(.get-syntax-literal! '<pos>)` call
+                                     (application (remap rator)
+                                                  ;; To support syntax objects, change the offset
+                                                  rands)]
+                                    [(and any-transformer-registers?
+                                          (eqv? transformer-register-pos (import-pos i)))
+                                     ;; This is a `(.set-transformer! '<sym> <expr>)` call
+                                     (void)]
+                                    [else #f]))]
                             [else #f]))))))
 
   (values body