linklet flattener: repair to name simplifier

The linklet flattener's name-simplification pass (intended to avoid
gratuitious changes in "startup.inc") didn't recognize all binding
forms.

racket/src/expander/expand/definition-context.rkt

@@ -92,7 +92,7 @@
       (define input-s (flip-introduction-scopes (add-intdef-scopes s all-intdefs) ctx))
       (define tmp-env (for/fold ([env (expand-context-env ctx)]) ([sym (in-list syms)]
                                                                   [intdef-id (in-list intdef-ids)])
-                        (hash-set env sym (local-variable intdef-id))))
+                        (env-extend env sym (local-variable intdef-id))))
       (log-expand ctx 'enter-bind)
       (define vals
         (eval-for-syntaxes-binding 'syntax-local-bind-syntaxes

racket/src/expander/expand/env.rkt

@@ -39,6 +39,8 @@
 (define empty-env #hasheq())
 (define (env-extend env key val)
   (hash-set env key val))
+(define (lookup env key default)
+  (hash-ref env key default))
 
 ;; `variable` is a token to represent a binding to a run-time variable
 (define variable (gensym 'variable))
@@ -134,13 +136,13 @@
     (define insp (and mi (module-instance-module mi) (module-inspector (module-instance-module mi))))
     (values t primitive? insp protected?)]
    [(local-binding? b)
-    (define t (hash-ref env (local-binding-key b) missing))
+    (define t (lookup env (local-binding-key b) missing))
     (cond
      [(eq? t missing)
       (values (or
                ;; check in lift envs, if any
                (for/or ([lift-env (in-list lift-envs)])
-                 (hash-ref (unbox lift-env) (local-binding-key b) #f))
+                 (lookup (unbox lift-env) (local-binding-key b) #f))
                (if out-of-context-as-variable?
                    variable
                    (error "identifier used out of context:" id)))

racket/src/expander/expand/lift-context.rkt

@@ -76,7 +76,7 @@
     (define keys
       (for/list ([id (in-list ids)])
         (define key (add-local-binding! id phase counter))
-        (set-box! lift-env (hash-set (unbox lift-env) key variable))
+        (set-box! lift-env (env-extend (unbox lift-env) key variable))
         key))
     (values ids (lifted-bind ids keys rhs))))
 

racket/src/expander/extract/underscore.rkt

@@ -80,8 +80,8 @@
                  (rename-vars formals replacements base-counts))
                `[,new-formals . ,(collapse-in-body body new-replacements new-base-counts)]))]
       [`(quote . ,_) e]
-      [`(let-values . _) (collapse-in-let e #f replacements base-counts)]
+      [`(let-values . ,_) (collapse-in-let e #f replacements base-counts)]
-      [`(letrec-values . _) (collapse-in-let e #t replacements base-counts)]
+      [`(letrec-values . ,_) (collapse-in-let e #t replacements base-counts)]
       [`(,pseudo-es ...) ; catch-all for remaining syntactic forms
        (collapse-in-body pseudo-es replacements base-counts)]
       [_ (if (symbol? e)
@@ -96,7 +96,7 @@
     (match e
       [`(,let-form ([,idss ,rhss] ...) ,body ...)
        (define-values (new-idss body-replacements body-base-counts)
-         (rename-vars idss replacements body-base-counts))
+         (rename-vars idss replacements base-counts))
        (define-values (rhs-replacements rhs-base-counts)
          (if rec?
              (values body-replacements body-base-counts)