diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index bac6c7162a45b..f0dea0c9bc89b 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -138,6 +138,9 @@ Bug Fixes to C++ Support
 - Fixed a bug where variables referenced by requires-clauses inside
   nested generic lambdas were not properly injected into the constraint scope.
   (`#73418 <https://github.com/llvm/llvm-project/issues/73418>`_)
+- Fixed a crash where substituting into a requires-expression that refers to function
+  parameters during the equivalence determination of two constraint expressions.
+  (`#74447 <https://github.com/llvm/llvm-project/issues/74447>`_)
 - Fixed deducing auto& from const int in template parameters of partial
   specializations.
   (`#77189 <https://github.com/llvm/llvm-project/issues/77189>`_)
diff --git a/clang/lib/Sema/SemaConcept.cpp b/clang/lib/Sema/SemaConcept.cpp
index 88fc846c89e42..19a460f411757 100644
--- a/clang/lib/Sema/SemaConcept.cpp
+++ b/clang/lib/Sema/SemaConcept.cpp
@@ -797,6 +797,15 @@ static const Expr *SubstituteConstraintExpressionWithoutSatisfaction(
   if (Inst.isInvalid())
     return nullptr;
 
+  // Set up a dummy 'instantiation' scope in the case of reference to function
+  // parameters that the surrounding function hasn't been instantiated yet. Note
+  // this may happen while we're comparing two templates' constraint
+  // equivalence.
+  LocalInstantiationScope ScopeForParameters(S);
+  if (auto *FD = llvm::dyn_cast<FunctionDecl>(DeclInfo.getDecl()))
+    for (auto *PVD : FD->parameters())
+      ScopeForParameters.InstantiatedLocal(PVD, PVD);
+
   std::optional<Sema::CXXThisScopeRAII> ThisScope;
   if (auto *RD = dyn_cast<CXXRecordDecl>(DeclInfo.getDeclContext()))
     ThisScope.emplace(S, const_cast<CXXRecordDecl *>(RD), Qualifiers());
diff --git a/clang/test/SemaTemplate/concepts-out-of-line-def.cpp b/clang/test/SemaTemplate/concepts-out-of-line-def.cpp
index c4e8e6f720c49..7323ad8d9ef2c 100644
--- a/clang/test/SemaTemplate/concepts-out-of-line-def.cpp
+++ b/clang/test/SemaTemplate/concepts-out-of-line-def.cpp
@@ -536,3 +536,25 @@ void X<T>::bar(decltype(requires { requires something_interesting<T>; })) {}
 template <class T>
 void X<T>::bar(decltype(requires { requires is_not_same_v<T, int>; })) {}
 } // namespace GH74314
+
+namespace GH74447 {
+template <typename T> struct S {
+  template <typename... U, int V>
+  void test(T target, U... value)
+    requires requires {
+      target;
+      sizeof...(value) == 1;
+      V == 2;
+    };
+};
+
+template <typename T>
+template <typename... U, int V>
+void S<T>::test(T target, U... value)
+  requires requires {
+    target;
+    sizeof...(value) == 1;
+    V == 2;
+  }
+{}
+} // namespace GH74447