improve error message for out-of-date module accesses

svn: r10990

src/mzscheme/src/env.c

@@ -2654,7 +2654,8 @@ scheme_lookup_binding(Scheme_Object *find_id, Scheme_Comp_Env *env, int flags,
     if (val && !(flags & SCHEME_NO_CERT_CHECKS))
       scheme_check_accessible_in_module(genv, env->insp, in_modidx, 
 					find_id, src_find_id, certs, NULL, -2, 0, 
-					NULL);
+					NULL,
+                                        env->genv);
   } else {
     /* Only try syntax table if there's not an explicit (later)
        variable mapping: */
@@ -2678,7 +2679,7 @@ scheme_lookup_binding(Scheme_Object *find_id, Scheme_Comp_Env *env, int flags,
     else
       pos = scheme_check_accessible_in_module(genv, env->insp, in_modidx, 
 					      find_id, src_find_id, certs, NULL, -1, 1,
-					      _protected);
+					      _protected, env->genv);
     modpos = SCHEME_INT_VAL(pos);
   } else
     modpos = -1;

src/mzscheme/src/eval.c

@@ -1835,7 +1835,8 @@ static Scheme_Object *link_module_variable(Scheme_Object *modidx,
     }
 
     if (!SAME_OBJ(menv, env)) {
-      varname = scheme_check_accessible_in_module(menv, insp, NULL, varname, NULL, NULL, insp, pos, 0, NULL);
+      varname = scheme_check_accessible_in_module(menv, insp, NULL, varname, NULL, NULL, 
+                                                  insp, pos, 0, NULL, env);
     }
   }
 
@@ -5551,7 +5552,7 @@ scheme_compile_expand_expr(Scheme_Object *form, Scheme_Comp_Env *env,
       SCHEME_EXPAND_OBSERVE_EXIT_PRIM(rec[drec].observer, form);
       SCHEME_EXPAND_OBSERVE_RETURN(rec[drec].observer, form);
       return form;
-    } else if (rec[drec].comp && SAME_OBJ(var, normal)) {
+    } else if (rec[drec].comp && SAME_OBJ(var, normal) && !rec[drec].observer) {
       /* Skip creation of intermediate form */
       Scheme_Syntax *f;
       taking_shortcut = 1;

src/mzscheme/src/module.c

@@ -3229,7 +3229,8 @@ static void check_certified(Scheme_Object *stx, Scheme_Object *certs,
 Scheme_Object *scheme_check_accessible_in_module(Scheme_Env *env, Scheme_Object *prot_insp, Scheme_Object *in_modidx,
 						 Scheme_Object *symbol, Scheme_Object *stx,
 						 Scheme_Object *certs, Scheme_Object *unexp_insp,
-						 int position, int want_pos, int *_protected)
+						 int position, int want_pos, int *_protected,
+                                                 Scheme_Env *from_env)
      /* Returns the actual name when !want_pos, needed in case of
 	uninterned names.  Otherwise, returns a position value on success.
 	If position < -1, then merely checks for protected syntax.
@@ -3354,10 +3355,27 @@ Scheme_Object *scheme_check_accessible_in_module(Scheme_Env *env, Scheme_Object
     symbol = stx;
     stx = NULL;
   }
-  scheme_wrong_syntax("compile", stx, symbol, 
+
-		      "variable not provided (directly or indirectly%s) from module: %D",
+  {
-		      (position >= 0) ? " and at the expected position" : "",
+    const char *srcstr;
-		      env->module->modname);
+    long srclen;
+    
+    if (from_env->module)
+      srcstr = scheme_display_to_string(from_env->module->modname, &srclen);
+    else {
+      srcstr = "";
+      srclen = 0;
+    }
+    
+    scheme_wrong_syntax("link", stx, symbol, 
+                        "module mismatch, probably from old bytecode whose dependencies have changed: "
+                        "variable not provided (directly or indirectly%s) from module: %D %s%t",
+                        (position >= 0) ? " and at the expected position" : "",
+                        env->module->modname,
+                        srclen ? "accessed from module: " : "",
+                        srcstr, srclen);
+  }
+
   return NULL;
 }
 

src/mzscheme/src/schpriv.h

@@ -2592,7 +2592,7 @@ Scheme_Object *scheme_check_accessible_in_module(Scheme_Env *env, Scheme_Object
 						 Scheme_Object *symbol, Scheme_Object *stx, 
 						 Scheme_Object *certs, Scheme_Object *unexp_insp,
 						 int position, int want_pos,
-						 int *_protected);
+						 int *_protected, Scheme_Env *from_env);
 Scheme_Object *scheme_module_syntax(Scheme_Object *modname, Scheme_Env *env, Scheme_Object *name);
 
 Scheme_Object *scheme_modidx_shift(Scheme_Object *modidx,