Fix literal matching for user-defined literals

change_notes/2026-05-21-fix-fp-rule-5-13-4.md

@@ -0,0 +1,5 @@
+- `RULE-5-13-4`, `M2-13-3` - `UnsignedIntegerLiteralsNotAppropriatelySuffixed.ql`, `MissingUSuffix.ql`:
+  - Remove FPs in user-defined literals and template instantiations.
+- `M2-13-3` - `cpp/autosar/missing-u-suffix`:
+  - Remove FPs in user-defined literals and template instantiations.
+

cpp/autosar/src/rules/A13-1-2/UserDefinedLiteralOperatorSuffixViolation.ql

@@ -17,7 +17,7 @@ import cpp
 import codingstandards.cpp.autosar
 import codingstandards.cpp.UserDefinedLiteral as udl
 
-from udl::UserDefinedLiteral udl
+from udl::UserDefinedLiteralDeclaration udl
 where
   not isExcluded(udl, NamingPackage::userDefinedLiteralOperatorSuffixViolationQuery()) and
   not udl.hasCompliantSuffix()

cpp/autosar/src/rules/A13-1-3/UserDefinedLiteralsOperatorsShallNotHaveSideEffects.ql

@@ -18,7 +18,7 @@ import codingstandards.cpp.UserDefinedLiteral as udl
 import codingstandards.cpp.SideEffect
 import codingstandards.cpp.sideeffect.DefaultEffects
 
-from udl::UserDefinedLiteral udl, SideEffect e
+from udl::UserDefinedLiteralDeclaration udl, SideEffect e
 where
   not isExcluded(udl,
     SideEffects2Package::userDefinedLiteralsOperatorsShallNotHaveSideEffectsQuery()) and

cpp/autosar/src/rules/A13-1-3/UserDefinedLiteralsOperatorsShallOnlyPerformConversionOfPassedParameters.ql

@@ -19,7 +19,7 @@ import codingstandards.cpp.autosar
 import codingstandards.cpp.UserDefinedLiteral as udl
 import codingstandards.cpp.SideEffect
 
-from udl::UserDefinedLiteral udl, Expr retExpr
+from udl::UserDefinedLiteralDeclaration udl, Expr retExpr
 where
   not isExcluded(udl,
     SideEffects2Package::userDefinedLiteralsOperatorsShallOnlyPerformConversionOfPassedParametersQuery()) and

cpp/cert/src/rules/DCL51-CPP/UseOfReservedLiteralSuffixIdentifier.ql

@@ -22,7 +22,7 @@ import cpp
 import codingstandards.cpp.cert
 import codingstandards.cpp.UserDefinedLiteral as udl
 
-from udl::UserDefinedLiteral udl
+from udl::UserDefinedLiteralDeclaration udl
 where
   not isExcluded(udl, NamingPackage::useOfReservedLiteralSuffixIdentifierQuery()) and
   not udl.hasCompliantSuffix()

cpp/common/src/codingstandards/cpp/Cpp14Literal.qll

@@ -5,9 +5,15 @@
  */
 module Cpp14Literal {
   private import cpp as StandardLibrary
+  private import codingstandards.cpp.UserDefinedLiteral
 
   /** An numeric literal. */
-  abstract class NumericLiteral extends StandardLibrary::Literal { }
+  abstract class NumericLiteral extends StandardLibrary::Literal {
+    NumericLiteral() {
+      // exclude user-defined literals as they define custom suffixes
+      not this instanceof UserDefinedLiteral
+    }
+  }
 
   /** Convenience for implementing class `UnrecognizedNumericLiteral` */
   abstract private class RecognizedNumericLiteral extends StandardLibrary::Literal { }

cpp/common/src/codingstandards/cpp/UserDefinedLiteral.qll

@@ -4,8 +4,17 @@
 
 import cpp
 
-class UserDefinedLiteral extends Function {
-  UserDefinedLiteral() {
+/**
+ * A user defined literal operator is a function that defines the behavior of a user defined literal.
+ * It is declared using the `operator ""` syntax.
+ * ```
+ * constexpr long operator""_km(unsigned long value) {
+ *   ...
+ * }
+ * ```
+ */
+class UserDefinedLiteralDeclaration extends Function {
+  UserDefinedLiteralDeclaration() {
     // We use the '?' in this regexp because CodeQL CLI 2.4.6 and earlier reported these operators
     // using a single ", i.e `operator "`. This has been fixed in 2.5.9 (at the latest), but I
     // don't know if upgraded older databases will still have the broken version in. I've therefore
@@ -16,3 +25,18 @@ class UserDefinedLiteral extends Function {
   /** Holds if `this` has a compliant suffix. */
   predicate hasCompliantSuffix() { this.getName().regexpMatch("operator \"\"?_\\p{Alpha}+") }
 }
+
+/**
+ * A user defined literal is a literal that is passed as an argument to a call to a user defined literal operator.
+ * ```
+ * 1000_km;
+ * ```
+ */
+class UserDefinedLiteral extends Literal {
+  UserDefinedLiteral() {
+    exists(FunctionCall fc |
+      this = fc.getArgument(0) and
+      fc.getTarget() instanceof UserDefinedLiteralDeclaration
+    )
+  }
+}

cpp/common/src/codingstandards/cpp/rules/unsignedintegerliteralsnotappropriatelysuffixed/UnsignedIntegerLiteralsNotAppropriatelySuffixed.qll

@@ -26,6 +26,8 @@ query predicate problems(Cpp14Literal::NumericLiteral nl, string message) {
     nl.getType().getUnspecifiedType().(IntegralType).isUnsigned() and
     // The literal already has a `u` or `U` suffix.
     not nl.getValueText().regexpMatch(".*[lL]*[uU][lL]*") and
+    // exclude literals derived from template instantiations
+    not nl.isFromTemplateInstantiation(_) and
     message = literalKind + " literal is an unsigned integer but does not include a 'U' suffix."
   )
 }

cpp/common/test/rules/unsignedintegerliteralsnotappropriatelysuffixed/test.cpp

@@ -543,4 +543,20 @@ void test_macro() {
   COMPLIANT_VAL;     // COMPLIANT
   NON_COMPLIANT_VAL; // NON_COMPLIANT[FALSE_NEGATIVE] - cannot determine suffix
                      // in macro expansions
-}
+}
+
+constexpr unsigned long long operator""_km(unsigned long long value) {
+  return value;
+}
+
+void test_user_defined_literal_exclusion() {
+  0x80000000_km; // COMPLIANT - user-defined literal argument should be excluded
+}
+
+template <typename T> unsigned long long instantiated_literal_exclusion() {
+  return T{}; // COMPLIANT - template instantiation should be excluded
+}
+
+void test_instantiated_literal_exclusion() {
+  instantiated_literal_exclusion<int>();
+}