Fix Issue 21936 - Segfault with -dip1000

src/dmd/access.d

@@ -48,8 +48,16 @@ bool checkAccess(AggregateDeclaration ad, Loc loc, Scope* sc, Dsymbol smember)
         return false; // for backward compatibility
     }
 
-    if (!symbolIsVisible(sc, smember) && (!(sc.flags & SCOPE.onlysafeaccess) || sc.func.setUnsafe()))
+    if (!symbolIsVisible(sc, smember))
     {
+        // when in @safe code or with -preview=dip1000
+        if (sc.flags & SCOPE.onlysafeaccess)
+        {
+            // if there is a func. ask for it's opinion of safety, and if it considers the access @safe accept it.
+            if (sc.func && !sc.func.setUnsafe())
+                return false;
+        }
+
         ad.error(loc, "member `%s` is not accessible%s", smember.toChars(), (sc.flags & SCOPE.onlysafeaccess) ? " from `@safe` code".ptr : "".ptr);
         //printf("smember = %s %s, vis = %d, semanticRun = %d\n",
         //        smember.kind(), smember.toPrettyChars(), smember.visible() smember.semanticRun);

test/fail_compilation/imports/issue21936s.d

@@ -0,0 +1,4 @@
+struct S
+{
+  private int field;
+}

test/fail_compilation/issue21936.d

@@ -0,0 +1,32 @@
+/* REQUIRED_ARGS: -preview=dip1000 -Ifail_compilation/imports
+TEST_OUTPUT:
+---
+fail_compilation/issue21936.d(15): Error: struct `issue21936s.S` member `field` is not accessible from `@safe` code
+fail_compilation/issue21936.d(15): Error: struct `issue21936s.S` member `field` is not accessible from `@safe` code
+fail_compilation/issue21936.d(11): Error: template instance `issue21936.constructImplicit!(S)` error instantiating
+fail_compilation/issue21936.d(7):        instantiated from here: `registerConstructors!(S)`
+fail_compilation/issue21936.d(21):        instantiated from here: `registerType!(S)`
+---
+*/
+#line 2
+module issue21936;
+import issue21936s;
+struct Handlers {
+    void registerType(T)()
+    {
+        registerConstructors!T;
+    }
+    void registerConstructors(T)()
+    {
+        constructImplicit!T;
+    }
+}
+
+auto constructImplicit(T)(typeof(T.init.tupleof) x = T.init.tupleof)
+{
+}
+
+void registerHandlersDateTime(Handlers handlers)
+{
+	handlers.registerType!(S);
+}