fix #13181: FP syntaxError with user-defined literal (#7172)

Author: ludviggunne

lib/token.cpp

@@ -126,7 +126,7 @@ void Token::update_property_info()
             else if (mTokType != eVariable && mTokType != eFunction && mTokType != eType && mTokType != eKeyword)
                 tokType(eName);
         } else if (simplecpp::Token::isNumberLike(mStr)) {
-            if (MathLib::isInt(mStr) || MathLib::isFloat(mStr))
+            if ((MathLib::isInt(mStr) || MathLib::isFloat(mStr)) && mStr.find('_') == std::string::npos)
                 tokType(eNumber);
             else
                 tokType(eName); // assume it is a user defined literal

test/testtokenize.cpp

@@ -78,6 +78,7 @@ class TestTokenizer : public TestFixture {
         TEST_CASE(tokenize37);  // #8550
         TEST_CASE(tokenize38);  // #9569
         TEST_CASE(tokenize39);  // #9771
+        TEST_CASE(tokenize40);  // #13181
 
         TEST_CASE(validate);
 
@@ -826,6 +827,17 @@ class TestTokenizer : public TestFixture {
         ASSERT_EQUALS(exp, tokenizeAndStringify(code));
     }
 
+    void tokenize40() { // #13181
+        const char code[] = "struct A { double eps(double); };\n"
+                            "A operator \"\"_a(long double);\n"
+                            "void f() {\n"
+                            "    double d = 1.23;\n"
+                            "    if (d == 1.2_a .eps(.1)) {}\n"
+                            "}\n";
+        (void) tokenizeAndStringify(code);
+        ASSERT_EQUALS("", errout_str());
+    }
+
     void validate() {
         // C++ code in C file
         ASSERT_THROW_INTERNAL(tokenizeAndStringify(";using namespace std;",false,Platform::Type::Native,false), SYNTAX);