Fix hashhash bug when there is null statement on the next line

Author: danmar

simplecpp.cpp

@@ -2132,7 +2132,7 @@ namespace simplecpp {
                     for (Token *b = tokensB.front(); b; b = b->next)
                         b->location = loc;
                     output->takeTokens(tokensB);
-                } else if (nextTok->op == '#' && nextTok->next->op == '#') {
+                } else if (sameline(B, nextTok) && sameline(B, nextTok->next) && nextTok->op == '#' && nextTok->next->op == '#') {
                     TokenList output2(files);
                     output2.push_back(new Token(strAB, tok->location));
                     nextTok = expandHashHash(&output2, loc, nextTok, macros, expandedmacros, parametertokens);

test.cpp

@@ -1207,6 +1207,18 @@ static void hashhash_invalid_missing_args()
     ASSERT_EQUALS("file0,1,syntax_error,failed to expand 'BAD', Invalid ## usage when expanding 'BAD': Missing first argument\n", toString(outputList));
 }
 
+static void hashhash_null_stmt()
+{
+    const char code[] =
+        "# define B(x) C ## x\n"
+        "#\n"
+        "# define C0 1\n"
+        "\n"
+        "B(0);\n";
+    simplecpp::OutputList outputList;
+    ASSERT_EQUALS("\n\n\n\n1 ;", preprocess(code, &outputList));
+}
+
 static void hashhash_universal_character()
 {
     const char code[] =
@@ -2636,6 +2648,7 @@ int main(int argc, char **argv)
     TEST_CASE(hashhash_invalid_2);
     TEST_CASE(hashhash_invalid_string_number);
     TEST_CASE(hashhash_invalid_missing_args);
+    TEST_CASE(hashhash_null_stmt);
     // C standard, 5.1.1.2, paragraph 4:
     //    If a character sequence that matches the syntax of a universal
     //    character name is produced by token concatenation (6.10.3.3),