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` - `cpp/misra/unsigned-integer-literals-not-appropriately-suffixed`:
+  - 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/common/src/codingstandards/cpp/Cpp14Literal.qll

@@ -5,9 +5,20 @@
  */
 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 exists(StandardLibrary::FunctionCall fc |
+        this = fc.getArgument(0) and
+        fc.getTarget() instanceof UserDefinedLiteral
+      ) and
+      // exclude literals derived from template instantiations
+      not this.isFromTemplateInstantiation(_)
+    }
+  }
 
   /** Convenience for implementing class `UnrecognizedNumericLiteral` */
   abstract private class RecognizedNumericLiteral extends StandardLibrary::Literal { }