From 180983fb4bb219ff6054c4f9f74fec782c75dbae Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Thu, 6 May 2021 07:02:22 -0600
Subject: [PATCH] cs: fix encuoraged and cross-module inlining of `set!`

When an inlined `set!` mutates a variable that's bound in the inlined
function, the `set!` target was not updated to refer to the inlined
binding.

Closes #3817
---
 pkgs/racket-test-core/tests/racket/optimize.rktl | 15 +++++++++++++++
 racket/src/cs/schemified/schemify.scm            | 10 ++++++----
 racket/src/schemify/inline.rkt                   |  2 +-
 3 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/pkgs/racket-test-core/tests/racket/optimize.rktl b/pkgs/racket-test-core/tests/racket/optimize.rktl
index 2a15f5a981..5469197024 100644
--- a/pkgs/racket-test-core/tests/racket/optimize.rktl
+++ b/pkgs/racket-test-core/tests/racket/optimize.rktl
@@ -7132,6 +7132,21 @@
 
         (f (+ 6.0 (one)) (+ 6.0 (one)))))
 
+;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Regression test to checking inlingin with `set!`:
+
+(module check-inline-of-set!-expression racket/base
+  (require racket/performance-hint)
+  (begin-encourage-inline
+    (define (f x)
+      (let ([y 0])
+        (set! y (+ y x))
+        y)))
+  (define result (list (f 1) (f 2)))
+  (provide result))
+
+(test '(1 2) dynamic-require ''check-inline-of-set!-expression 'result)
+
 ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (report-errs)
diff --git a/racket/src/cs/schemified/schemify.scm b/racket/src/cs/schemified/schemify.scm
index faa5b1c912..e4efda2b5c 100644
--- a/racket/src/cs/schemified/schemify.scm
+++ b/racket/src/cs/schemified/schemify.scm
@@ -12722,10 +12722,12 @@
                                           (values id_1 rhs_0)))))))
                               (case-lambda
                                ((id_0 rhs_0)
-                                (list
-                                 'set!
-                                 id_0
-                                 (clone-expr rhs_0 env_0 mutated_0)))
+                                (let ((app_0
+                                       (clone-expr id_0 env_0 mutated_0)))
+                                  (list
+                                   'set!
+                                   app_0
+                                   (clone-expr rhs_0 env_0 mutated_0))))
                                (args
                                 (raise-binding-result-arity-error 2 args))))
                              (if (if (eq? '|#%variable-reference| hd_0)
diff --git a/racket/src/schemify/inline.rkt b/racket/src/schemify/inline.rkt
index 3098caa5b6..5079754545 100644
--- a/racket/src/schemify/inline.rkt
+++ b/racket/src/schemify/inline.rkt
@@ -207,7 +207,7 @@
      [`(begin-unsafe ,exps ...)
       `(begin-unsafe . ,(clone-body exps env mutated))]
      [`(set! ,id ,rhs)
-      `(set! ,id ,(clone-expr rhs env mutated))]
+      `(set! ,(clone-expr id env mutated) ,(clone-expr rhs env mutated))]
      [`(#%variable-reference) v]
      [`(#%variable-reference ,id)
       `(#%variable-reference ,(clone-expr id env mutated))]