diff --git a/lib/library.cpp b/lib/library.cpp
index a85d7e1b5..199bc0ea4 100644
--- a/lib/library.cpp
+++ b/lib/library.cpp
@@ -181,6 +181,8 @@ Library::Error Library::load(const tinyxml2::XMLDocument &doc)
                         else if (strcmp(argnode->Name(), "valid") == 0) {
                             // Validate the validation expression
                             const char *p = argnode->GetText();
+                            if (*p == '-')
+                                ++p;
                             if (!std::isdigit(*p))
                                 return Error(BAD_ATTRIBUTE_VALUE, argnode->GetText());
                             for (; *p; p++) {
@@ -321,6 +323,10 @@ bool Library::isargvalid(const std::string &functionName, int argnr, const MathL
     TokenList tokenList(0);
     std::istringstream istr(ac->valid + ',');
     tokenList.createTokens(istr,"");
+    if (Token::Match(tokenList.front(), "- %num% -")) {
+        tokenList.front()->str("-" + tokenList.front()->strAt(1));
+        tokenList.front()->deleteNext();
+    }
     for (const Token *tok = tokenList.front(); tok; tok = tok->next()) {
         if (tok->isNumber() && argvalue == MathLib::toLongNumber(tok->str()))
             return true;
diff --git a/test/testlibrary.cpp b/test/testlibrary.cpp
index 6f237fa10..e036ca7fb 100644
--- a/test/testlibrary.cpp
+++ b/test/testlibrary.cpp
@@ -33,6 +33,7 @@ private:
         TEST_CASE(function);
         TEST_CASE(function_arg);
         TEST_CASE(function_arg_any);
+        TEST_CASE(function_arg_valid);
         TEST_CASE(memory);
         TEST_CASE(memory2); // define extra "free" allocation functions
         TEST_CASE(resource);
@@ -76,8 +77,7 @@ private:
                                "    <arg nr=\"2\"><not-null/></arg>\n"
                                "    <arg nr=\"3\"><formatstr/></arg>\n"
                                "    <arg nr=\"4\"><strz/></arg>\n"
-                               "    <arg nr=\"5\"><valid>1-</valid></arg>\n"
-                               "    <arg nr=\"6\"><not-bool/></arg>\n"
+                               "    <arg nr=\"5\"><not-bool/></arg>\n"
                                "  </function>\n"
                                "</def>";
         tinyxml2::XMLDocument doc;
@@ -89,8 +89,7 @@ private:
         ASSERT_EQUALS(true, library.argumentChecks["foo"][2].notnull);
         ASSERT_EQUALS(true, library.argumentChecks["foo"][3].formatstr);
         ASSERT_EQUALS(true, library.argumentChecks["foo"][4].strz);
-        ASSERT_EQUALS("1-", library.argumentChecks["foo"][5].valid);
-        ASSERT_EQUALS(true, library.argumentChecks["foo"][6].notbool);
+        ASSERT_EQUALS(true, library.argumentChecks["foo"][5].notbool);
     }
 
     void function_arg_any() const {
@@ -108,6 +107,45 @@ private:
         ASSERT_EQUALS(true, library.argumentChecks["foo"][-1].notuninit);
     }
 
+    void function_arg_valid() const {
+        const char xmldata[] = "<?xml version=\"1.0\"?>\n"
+                               "<def>\n"
+                               "  <function name=\"foo\">\n"
+                               "    <arg nr=\"1\"><valid>1-</valid></arg>\n"
+                               "    <arg nr=\"2\"><valid>-7-0</valid></arg>\n"
+                               "    <arg nr=\"3\"><valid>1-5,8</valid></arg>\n"
+                               "  </function>\n"
+                               "</def>";
+        tinyxml2::XMLDocument doc;
+        doc.Parse(xmldata, sizeof(xmldata));
+
+        Library library;
+        library.load(doc);
+
+        // 1-
+        ASSERT_EQUALS(false, library.isargvalid("foo", 1, -10));
+        ASSERT_EQUALS(false, library.isargvalid("foo", 1, 0));
+        ASSERT_EQUALS(true, library.isargvalid("foo", 1, 1));
+        ASSERT_EQUALS(true, library.isargvalid("foo", 1, 10));
+
+        // -7-0
+        ASSERT_EQUALS(false, library.isargvalid("foo", 2, -10));
+        ASSERT_EQUALS(true,  library.isargvalid("foo", 2, -7));
+        ASSERT_EQUALS(true,  library.isargvalid("foo", 2, -3));
+        ASSERT_EQUALS(true,  library.isargvalid("foo", 2, 0));
+        ASSERT_EQUALS(false, library.isargvalid("foo", 2, 1));
+
+        // 1-5,8
+        ASSERT_EQUALS(false, library.isargvalid("foo", 3, 0));
+        ASSERT_EQUALS(true,  library.isargvalid("foo", 3, 1));
+        ASSERT_EQUALS(true,  library.isargvalid("foo", 3, 3));
+        ASSERT_EQUALS(true,  library.isargvalid("foo", 3, 5));
+        ASSERT_EQUALS(false, library.isargvalid("foo", 3, 6));
+        ASSERT_EQUALS(false, library.isargvalid("foo", 3, 7));
+        ASSERT_EQUALS(true,  library.isargvalid("foo", 3, 8));
+        ASSERT_EQUALS(false, library.isargvalid("foo", 3, 9));
+    }
+
     void memory() const {
         const char xmldata[] = "<?xml version=\"1.0\"?>\n"
                                "<def>\n"