Preserve newline and space during macro expansion

preprocess.c

@@ -532,6 +532,8 @@ static Token *subst(Token *tok, MacroArg *args) {
     // before they are substituted into a macro body.
     if (arg) {
       Token *t = preprocess2(arg->tok);
+      t->at_bol = tok->at_bol;
+      t->has_space = tok->has_space;
       for (; t->kind != TK_EOF; t = t->next)
         cur = cur->next = copy_token(t);
       tok = tok->next;
@@ -563,6 +565,8 @@ static bool expand_macro(Token **rest, Token *tok) {
     Hideset *hs = hideset_union(tok->hideset, new_hideset(m->name));
     Token *body = add_hideset(m->body, hs);
     *rest = append(body, tok->next);
+    (*rest)->at_bol = tok->at_bol;
+    (*rest)->has_space = tok->has_space;
     return true;
   }
 
@@ -587,6 +591,8 @@ static bool expand_macro(Token **rest, Token *tok) {
   Token *body = subst(m->body, args);
   body = add_hideset(body, hs);
   *rest = append(body, tok->next);
+  (*rest)->at_bol = macro_token->at_bol;
+  (*rest)->has_space = macro_token->has_space;
   return true;
 }
 

test/macro.c

@@ -290,6 +290,22 @@ int main() {
 #endif
   ASSERT(5, m);
 
+#define STR(x) #x
+#define M12(x) STR(x)
+#define M13(x) M12(foo.x)
+  ASSERT(0, strcmp(M13(bar), "foo.bar"));
+
+#define M13(x) M12(foo. x)
+  ASSERT(0, strcmp(M13(bar), "foo. bar"));
+
+#define M12 foo
+#define M13(x) STR(x)
+#define M14(x) M13(x.M12)
+  ASSERT(0, strcmp(M14(bar), "bar.foo"));
+
+#define M14(x) M13(x. M12)
+  ASSERT(0, strcmp(M14(bar), "bar. foo"));
+
   printf("OK\n");
   return 0;
 }