Fix #356: CI can now fail on UBSan findings and clang-tidy warnings

Two CI jobs were structurally unable to fail on the defect class they
exist to catch: GCC UBSan recovers by default (prints and exits 0, so
the sanitizer leg only enforced the ASan half), and clang-tidy exits 0
on warnings with WarningsAsErrors unset.

- Sanitizer blocks (library + parser) add -fno-sanitize-recover=
  undefined. Verified locally: the full suite passes under fatal
  ASan+UBSan (the real UB this would have caught was fixed in #349
  and #361 first).
- The clang-tidy workflow adds --warnings-as-errors='*', and the
  15-warning baseline is fixed in the same change (no-op std::move on
  const-ref args and a trivially-copyable variant, missing override on
  two rebuild-visitor dtors, std::move on a forwarding reference,
  a cloned constexpr branch merged, a value param made const-ref, and
  a NOLINT that sat on the wrong line), so the job starts green.

Signed-off-by: petlenz <peterlenz89.pl@gmail.com>

Author: petlenz

.github/workflows/clang-tidy-check.yml

@@ -30,4 +30,4 @@ jobs:
       - name: Run clang-tidy
         run: |
           find src -name '*.cpp' -print0 \
-          | xargs -0 clang-tidy-18 -p build
+          | xargs -0 clang-tidy-18 -p build --warnings-as-errors='*'

CMakeLists.txt

@@ -194,9 +194,10 @@ endif()
 # Sanitizers
 if(NUMSIM_CAS_SANITIZERS)
     target_compile_options(${PROJECT_NAME} PUBLIC
-        -fsanitize=address,undefined -fno-omit-frame-pointer)
+        -fsanitize=address,undefined -fno-sanitize-recover=undefined
+        -fno-omit-frame-pointer)
     target_link_options(${PROJECT_NAME} PUBLIC
-        -fsanitize=address,undefined)
+        -fsanitize=address,undefined -fno-sanitize-recover=undefined)
 endif()
 
 # Optional convenience for Windows
@@ -274,9 +275,10 @@ if(NUMSIM_CAS_BUILD_PARSER)
 
   if(NUMSIM_CAS_SANITIZERS)
     target_compile_options(NumSim_CAS_Parser PUBLIC
-      -fsanitize=address,undefined -fno-omit-frame-pointer)
+      -fsanitize=address,undefined -fno-sanitize-recover=undefined
+      -fno-omit-frame-pointer)
     target_link_options(NumSim_CAS_Parser PUBLIC
-      -fsanitize=address,undefined)
+      -fsanitize=address,undefined -fno-sanitize-recover=undefined)
   endif()
 
   if(WIN32)

include/numsim_cas/core/scalar_number.h

@@ -96,7 +96,7 @@ class scalar_number {
                                           scalar_number const &exp);
 
 private:
-  explicit scalar_number(variant_t vv) : v_(std::move(vv)) {
+  explicit scalar_number(variant_t vv) : v_(vv) {
     if (auto *r = std::get_if<rational_t>(&v_)) {
       if (r->den == 1)
         v_ = r->num;

include/numsim_cas/parser/parse_error.h

@@ -37,7 +37,7 @@ class parse_error : public cas_error {
 public:
   /// Construct with optional source context. Pass an empty `source` and
   /// `byte_offset = 0` for errors raised outside the parser.
-  parse_error(std::string message, std::size_t byte_offset,
+  parse_error(std::string const &message, std::size_t byte_offset,
               std::string_view source);
 
   /// Byte offset into the source where the error was detected, clamped

include/numsim_cas/scalar/visitors/scalar_rebuild_visitor.h

@@ -14,7 +14,7 @@ class scalar_rebuild_visitor : public scalar_visitor_const_t {
 public:
   using expr_holder_t = expression_holder<scalar_expression>;
 
-  virtual ~scalar_rebuild_visitor() = default;
+  ~scalar_rebuild_visitor() override = default;
 
   virtual expr_holder_t apply(expr_holder_t const &expr) {
     if (expr.is_valid()) {

include/numsim_cas/tensor/wrappers/tensor_inv.h

@@ -12,8 +12,8 @@ class tensor_inv final : public unary_op<tensor_node_base_t<tensor_inv>> {
   using base = unary_op<tensor_node_base_t<tensor_inv>>;
 
   template <typename Expr>
-  explicit tensor_inv(
-      Expr &&_expr) // NOLINT(bugprone-forwarding-reference-overload)
+  // NOLINTNEXTLINE(bugprone-forwarding-reference-overload)
+  explicit tensor_inv(Expr &&_expr)
       : base(std::forward<Expr>(_expr), _expr.get().dim(), _expr.get().rank()) {
     // ── Rank gate (#292) ──────────────────────────────────────────
     // Mirror the inv() factory's rank gate (tensor_functions.h:467)

include/numsim_cas/tensor_to_scalar/visitors/tensor_to_scalar_rebuild_visitor.h

@@ -19,7 +19,7 @@ class tensor_to_scalar_rebuild_visitor
   using scalar_holder_t = expression_holder<scalar_expression>;
   using tensor_holder_t = expression_holder<tensor_expression>;
 
-  virtual ~tensor_to_scalar_rebuild_visitor() = default;
+  ~tensor_to_scalar_rebuild_visitor() override = default;
 
   virtual t2s_holder_t apply(t2s_holder_t const &expr) {
     if (expr.is_valid()) {

include/numsim_cas/tensor_to_scalar/visitors/tensor_to_scalar_substitution.h

@@ -45,9 +45,8 @@ class tensor_to_scalar_substitution final
   }
 
   tensor_holder_t apply_tensor(tensor_holder_t const &expr) override {
-    if constexpr (std::is_same_v<TargetBase, tensor_expression>) {
-      return substitute(expr, m_old, m_new);
-    } else if constexpr (std::is_same_v<TargetBase, scalar_expression>) {
+    if constexpr (std::is_same_v<TargetBase, tensor_expression> ||
+                  std::is_same_v<TargetBase, scalar_expression>) {
       return substitute(expr, m_old, m_new);
     } else {
       return expr;

src/numsim_cas/parser/parse_error.cpp

@@ -63,7 +63,7 @@ std::string format_message(std::string_view body, std::string_view source,
 
 } // namespace
 
-parse_error::parse_error(std::string message, std::size_t byte_offset,
+parse_error::parse_error(std::string const &message, std::size_t byte_offset,
                          std::string_view source)
     : cas_error(format_message(message, source, byte_offset)) {
   if (!source.empty()) {

src/numsim_cas/parser/parser.cpp

@@ -38,7 +38,7 @@ syntax_error translate_pegtl_error(pegtl::parse_error const &e,
   // returns a string_view from message() which can't directly
   // construct a std::string by '='.
   std::string msg(e.message());
-  return syntax_error(std::move(msg), byte, source);
+  return syntax_error(msg, byte, source);
 }
 
 // #355 — PEGTL parses by C++ recursion; deeply nested input overflows the
@@ -150,7 +150,7 @@ parsed_expression parse(std::string_view source, symbol_table &syms) {
               "bracket-list literal '[...]' cannot be a top-level expression",
               source.size(), source);
         } else {
-          return std::move(v);
+          return std::forward<decltype(v)>(v);
         }
       },
       std::move(state.values.front()));