special treatment of void as 'inferred-name property

allows keyword-based application to hide temporary
 names that happen to be bound to procedure arguments

collects/racket/private/kw.rkt

@@ -821,7 +821,11 @@
                   [(keyword? (syntax-e (car l)))
                    (loop (cddr l)
                          (cdr ids)
-                         (cons (list (car ids) (cadr l)) bind-accum)
+                         (cons (list (car ids) (syntax-property (cadr l)
+                                                                'inferred-name
+                                                                ;; void hides binding name
+                                                                (void)))
+                               bind-accum)
                          arg-accum
                          (cons (cons (car l) (car ids))
                                kw-pairs))]

collects/racket/private/name.rkt

@@ -4,8 +4,12 @@
   (#%provide syntax-local-infer-name)
   
   (define (syntax-local-infer-name stx)
-    (or (syntax-property stx 'inferred-name)
-	(let ([n (syntax-local-name)])
+    (let-values ([(prop) (syntax-property stx 'inferred-name)])
+      (or (and prop
+               (not (void? prop))
+               prop)
+          (let ([n (and (not (void? prop))
+                        (syntax-local-name))])
             (or n
                 (let ([s (syntax-source stx)])
                   (and s
@@ -22,4 +26,4 @@
                          (if l
                              (string->symbol (format "~a:~a:~a" s l c))
                              (let ([p (syntax-position stx)])
-			     (string->symbol (format "~a::~a" s p))))))))))))
+                               (string->symbol (format "~a::~a" s p)))))))))))))

collects/scribblings/reference/syntax-model.scrbl

@@ -968,7 +968,10 @@ When an @indexed-racket['inferred-name] property is attached to a
 syntax object for an expression (see @secref["stxprops"]), the
 property value is used for naming the expression, and it overrides any
 name that was inferred from the expression's context. Normally, the
-property value should be a symbol or an identifier.
+property value should be a symbol. A @racket['inferred-name] 
+property value of @|void-const| hides a name that would otherwise be
+inferred from context (perhaps because a binding identifier's was 
+automatically generated and should not be exposed).
 
 When an inferred name is not available, but a source location is
 available, a name is constructed using the source location

collects/syntax/scribblings/name.scrbl

@@ -11,6 +11,7 @@
 Similar to @scheme[syntax-local-name] except that @scheme[stx] is
 checked for an @scheme['inferred-name] property (which overrides any
 inferred name). If neither @scheme[syntax-local-name] nor
-@scheme['inferred-name] produce a name, then a name is constructed
-from the source-location information in @scheme[stx], if any. If no
-name can be constructed, the result is @scheme[#f].}
+@scheme['inferred-name] produce a name, or if the
+@scheme['inferred-name] property value is @|void-const|, then a name
+is constructed from the source-location information in @scheme[stx],
+if any. If no name can be constructed, the result is @scheme[#f].}

doc/release-notes/racket/HISTORY.txt

@@ -2,6 +2,7 @@ Version 5.1.0.4
 Change file-or-directory-permission to add 'bits mode
  and permission-setting mode
 racket/file: add user-read-bit, etc.
+Added special treatment of void as an 'inferred-name property
 
 Version 5.1.0.2
 Enabled single-precision floats by default

src/racket/src/fun.c

@@ -1944,6 +1944,10 @@ Scheme_Object *scheme_build_closure_name(Scheme_Object *code, Scheme_Compile_Inf
   name = scheme_stx_property(code, scheme_inferred_name_symbol, NULL);
   if (name && SCHEME_SYMBOLP(name)) {
     name = combine_name_with_srcloc(name, code, 0);
+  } else if (name && SCHEME_VOIDP(name)) {
+    name = scheme_source_to_name(code);
+    if (name)
+      name = combine_name_with_srcloc(name, code, 1);
   } else {
     name = rec[drec].value_name;
     if (!name || SCHEME_FALSEP(name)) {