From d96937ceb380ac353e873574a479196acb45ab9c Mon Sep 17 00:00:00 2001
From: "petro.zarytskyi" <petro.zarytskyi@gmail.com>
Date: Mon, 9 Dec 2024 22:16:03 +0200
Subject: [PATCH] warn fix

---
 lib/Differentiator/ReverseModeVisitor.cpp | 23 ++++++++++++----
 test/Gradient/UserDefinedTypes.C          | 33 ++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 6 deletions(-)

diff --git a/lib/Differentiator/ReverseModeVisitor.cpp b/lib/Differentiator/ReverseModeVisitor.cpp
index ec4862b3f..beaa21a9e 100644
--- a/lib/Differentiator/ReverseModeVisitor.cpp
+++ b/lib/Differentiator/ReverseModeVisitor.cpp
@@ -4281,12 +4281,25 @@ Expr* getArraySizeExpr(const ArrayType* AT, ASTContext& context,
             CE->getConstructor(), primalArgs, reverseForwAdjointArgs,
             /*baseExpr=*/nullptr)) {
       if (RD->isAggregate()) {
-        diag(DiagnosticsEngine::Note, CE->getConstructor()->getBeginLoc(),
-             "No need to provide a custom constructor forward sweep for an "
-             "aggregate type.");
+        // set up printing policy
+        clang::LangOptions LangOpts;
+        LangOpts.CPlusPlus = true;
+        clang::PrintingPolicy Policy(LangOpts);
+        Policy.Bool = true;
+        SmallString<128> Name_class;
+        llvm::raw_svector_ostream OS_class(Name_class);
+        RD->getNameForDiagnostic(OS_class, Policy, /*qualified=*/true);
         diag(DiagnosticsEngine::Warning, CE->getBeginLoc(),
-             "No need to provide a custom constructor forward sweep for an "
-             "aggregate type.");
+             "'%0' is an aggregate type and its constructor does not require a "
+             "user-defined forward sweep function",
+             {OS_class.str()});
+        const FunctionDecl* constr_forw =
+            cast<CallExpr>(customReverseForwFnCall)->getDirectCallee();
+        SmallString<128> Name_forw;
+        llvm::raw_svector_ostream OS_forw(Name_forw);
+        constr_forw->getNameForDiagnostic(OS_forw, Policy, /*qualified=*/true);
+        diag(DiagnosticsEngine::Note, constr_forw->getBeginLoc(),
+             "'%0' is defined here", {OS_forw.str()});
       }
       Expr* callRes = StoreAndRef(customReverseForwFnCall);
       Expr* val =
diff --git a/test/Gradient/UserDefinedTypes.C b/test/Gradient/UserDefinedTypes.C
index 6e2580a01..5c320afef 100644
--- a/test/Gradient/UserDefinedTypes.C
+++ b/test/Gradient/UserDefinedTypes.C
@@ -1,4 +1,4 @@
-// RUN: %cladclang %s -I%S/../../include -oUserDefinedTypes.out 2>&1 | %filecheck %s
+// RUN: %cladclang %s -I%S/../../include -oUserDefinedTypes.out -Xclang -verify 2>&1 | %filecheck %s
 // RUN: ./UserDefinedTypes.out | %filecheck_exec %s
 // RUN: %cladclang -Xclang -plugin-arg-clad -Xclang -enable-tbr %s -I%S/../../include -oUserDefinedTypes.out
 // RUN: ./UserDefinedTypes.out | %filecheck_exec %s
@@ -485,6 +485,35 @@ double fn14(double x, double y) {
 // CHECK-NEXT:     }
 // CHECK-NEXT:}
 
+namespace clad {
+namespace custom_derivatives {
+namespace class_functions {
+template<::std::size_t N>
+::clad::ValueAndAdjoint<::std::array<double, N>, ::std::array<double, N>> // expected-note {{'clad::custom_derivatives::class_functions::constructor_reverse_forw<2UL>' is defined here}}
+constructor_reverse_forw(::clad::ConstructorReverseForwTag<::std::array<double, N>>) {
+  ::std::array<double, N> a;
+  ::std::array<double, N> d_a;
+  return {a, d_a};
+}
+}}}
+
+double fn15(double x, double y) {
+  std::array<double, 2> arr; // expected-warning {{'std::array<double, 2>' is an aggregate type and its constructor does not require a user-defined forward sweep function}}
+  return arr[0];
+}
+
+// CHECK:void fn15_grad(double x, double y, double *_d_x, double *_d_y) {
+// CHECK-NEXT:    ::clad::ValueAndAdjoint< ::std::array<double, 2UL>, ::std::array<double, 2UL> > _t0 = {{.*}}constructor_reverse_forw(clad::ConstructorReverseForwTag<array<double, 2> >());
+// CHECK-NEXT:    std::array<double, 2> _d_arr(_t0.adjoint);
+// CHECK-NEXT:    std::array<double, 2> arr(_t0.value);
+// CHECK-NEXT:    std::array<double, 2> _t1 = arr;
+// CHECK-NEXT:    clad::ValueAndAdjoint<reference, reference> _t2 = _t1.operator_subscript_forw(0, &_d_arr, 0);
+// CHECK-NEXT:    {
+// CHECK-NEXT:        std::array::size_type _r0 = 0UL;
+// CHECK-NEXT:        _t1.operator_subscript_pullback(0, 1, &_d_arr, &_r0);
+// CHECK-NEXT:    }
+// CHECK-NEXT:}
+
 void print(const Tangent& t) {
   for (int i = 0; i < 5; ++i) {
     printf("%.2f", t.data[i]);
@@ -556,6 +585,8 @@ int main() {
 
     INIT_GRADIENT(fn14);
     TEST_GRADIENT(fn14, /*numOfDerivativeArgs=*/2, 3, 5, &d_i, &d_j);    // CHECK-EXEC: {30.00, 22.00}
+
+    INIT_GRADIENT(fn15);
 }
 
 // CHECK: void sum_pullback(Tangent &t, double _d_y, Tangent *_d_t) {