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

@@ -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)

racket/src/cs/schemified/schemify.scm

@@ -12722,10 +12722,12 @@
                                           (values id_1 rhs_0)))))))
                               (case-lambda
                                ((id_0 rhs_0)
-                                (list
+                                (let ((app_0
-                                 'set!
+                                       (clone-expr id_0 env_0 mutated_0)))
-                                 id_0
+                                  (list
-                                 (clone-expr rhs_0 env_0 mutated_0)))
+                                   '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)

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))]