src/dinterpret.d

@@ -1470,7 +1470,7 @@ public:
                 result = e; // bubbled up from ReturnStatement
                 return;
             }
-            e = interpret(s.increment, istate); // TODO: ctfeNeedNothing is better?
+            e = interpret(s.increment, istate, ctfeNeedNothing);
             if (exceptionOrCant(e))
                 return;
         }
@@ -5459,9 +5459,9 @@ public:
         if (exceptionOrCant(e1))
             return;
         // If the expression has been cast to void, do nothing.
-        if (e.to.ty == Tvoid && goal == ctfeNeedNothing)
+        if (e.to.ty == Tvoid)
         {
-            result = e1;
+            result = CTFEExp.voidexp;
             return;
         }
         if (e.to.ty == Tpointer && e1.op != TOKnull)

src/inline.d

@@ -2145,7 +2145,20 @@ void expandInline(FuncDeclaration fd, FuncDeclaration parent, Expression eret,
             if (vfrom.type.ty == Tdelegate ||
                 vfrom.type.ty == Tpointer && vfrom.type.nextOf().ty == Tfunction)
             {
-                again = true;
+                if (arg.op == TOKvar)
+                {
+                    VarExp ve = cast(VarExp)arg;
+                    if (ve.var.isFuncDeclaration())
+                        again = true;
+                }
+                else if (arg.op == TOKsymoff)
+                {
+                    SymOffExp se = cast(SymOffExp)arg;
+                    if (se.var.isFuncDeclaration())
+                        again = true;
+                }
+                else if (arg.op == TOKfunction || arg.op == TOKdelegate)
+                    again = true;
             }
         }
     }

test/compilable/interpret3.d

@@ -7664,3 +7664,17 @@ struct Tok15233 {}
 enum tup15233 = TT15233!(Tok15233(), "foo");
 static assert(tup15233[0] == Tok15233());
 static assert(tup15233[1] == "foo");
+
+/**************************************************
+    15251 - void cast in ForStatement.increment
+**************************************************/
+
+int test15251()
+{
+    for (ubyte lwr = 19;
+        lwr != 20;
+        cast(void)++lwr)    // have to to be evaluated with ctfeNeedNothing
+    {}
+    return 1;
+}
+static assert(test15251());

test/runnable/inline.d

@@ -922,6 +922,29 @@ void test15207()
     auto c = new C15207();
 }
 
+/**********************************/
+// 15253
+
+struct MessageType15253
+{
+    MessageType15253[] messageTypes;
+
+    const void toString1(scope void delegate(const(char)[]) sink)
+    {
+        messageTypes[0].toString1(sink);
+    }
+}
+
+struct ProtoPackage15253
+{
+    MessageType15253[] messageTypes;
+
+    const void toString1(scope void delegate(const(char)[]) sink)
+    {
+        messageTypes[0].toString1(sink);
+    }
+}
+
 /**********************************/
 
 int main()