diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp
--- a/clang/lib/AST/DeclCXX.cpp
+++ b/clang/lib/AST/DeclCXX.cpp
@@ -1379,6 +1379,11 @@
 
 void CXXRecordDecl::addedEligibleSpecialMemberFunction(const CXXMethodDecl *MD,
                                                unsigned SMKind) {
+  if (MD->getDescribedFunctionTemplate())
+    // This happens only when we get a template default constructor.
+    // We don't want it to affect DeclaredNonTrivialSpecialMembers because
+    // it shouldn't make a class non-trivial. (GH59206)
+    return;
   if (const auto *DD = dyn_cast<CXXDestructorDecl>(MD)) {
     if (DD->isUserProvided())
       data().HasIrrelevantDestructor = false;
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -18193,8 +18193,11 @@
                                               CXXMethodDecl *M1,
                                               CXXMethodDecl *M2,
                                               Sema::CXXSpecialMember CSM) {
+  // We don't compare templates to non-templates: See
+  // https://github.com/llvm/llvm-project/issues/59206
   if (CSM == Sema::CXXDefaultConstructor)
-    return true;
+    return bool(M1->getDescribedFunctionTemplate()) ==
+           bool(M2->getDescribedFunctionTemplate());
   if (!Context.hasSameType(M1->getParamDecl(0)->getType(),
                            M2->getParamDecl(0)->getType()))
     return false;
diff --git a/clang/test/SemaCXX/constrained-special-member-functions.cpp b/clang/test/SemaCXX/constrained-special-member-functions.cpp
--- a/clang/test/SemaCXX/constrained-special-member-functions.cpp
+++ b/clang/test/SemaCXX/constrained-special-member-functions.cpp
@@ -225,3 +225,41 @@
   S<2, 2> s2;
 }
 }
+
+namespace GH59206 {
+
+struct A {
+  A() = default; //eligible, second constructor unsatisfied
+  template<class... Args>
+  A(Args&&... args) requires (sizeof...(Args) > 0) {}
+};
+
+struct B {
+  B() = default; //ineligible, second constructor more constrained
+  template<class... Args>
+  B(Args&&... args) requires (sizeof...(Args) == 0) {}
+};
+
+struct C {
+  C() = default; //eligible, but
+  template<class... Args> //also eligible and non-trivial
+  C(Args&&... args) {}
+};
+
+struct D : B {};
+
+static_assert(__is_trivially_copyable(A), "");
+static_assert(__is_trivially_copyable(B), "");
+static_assert(__is_trivially_copyable(C), "");
+static_assert(__is_trivially_copyable(D), "");
+
+static_assert(__is_trivial(A), "");
+static_assert(__is_trivial(B), "");
+static_assert(__is_trivial(C), "");
+static_assert(__is_trivial(D), "");
+static_assert(__is_trivially_constructible(A), "");
+static_assert(__is_trivially_constructible(B), "");
+static_assert(__is_trivially_constructible(C), "");
+static_assert(__is_trivially_constructible(D), "");
+
+}