diff --git a/clang/include/clang/AST/ExprConcepts.h b/clang/include/clang/AST/ExprConcepts.h
--- a/clang/include/clang/AST/ExprConcepts.h
+++ b/clang/include/clang/AST/ExprConcepts.h
@@ -528,6 +528,12 @@
     return RequiresExprBits.IsSatisfied;
   }
 
+  void setSatisfied(bool IsSatisfied) {
+    assert(!isValueDependent() &&
+           "setSatisfied called on a dependent RequiresExpr");
+    RequiresExprBits.IsSatisfied = IsSatisfied;
+  }
+
   SourceLocation getRequiresKWLoc() const {
     return RequiresExprBits.RequiresKWLoc;
   }
diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -3507,6 +3507,8 @@
   //   Expressions appearing within a requirement-body are unevaluated operands.
   EnterExpressionEvaluationContext Ctx(
       Actions, Sema::ExpressionEvaluationContext::Unevaluated);
+  // Non dependent diagnostics must be undelayed.
+  Sema::ContextRAII UndelayDiagnostics(Actions, Actions.CurContext);
 
   ParseScope BodyScope(this, Scope::DeclScope);
   RequiresExprBodyDecl *Body = Actions.ActOnStartRequiresExpr(
diff --git a/clang/lib/Sema/SemaConcept.cpp b/clang/lib/Sema/SemaConcept.cpp
--- a/clang/lib/Sema/SemaConcept.cpp
+++ b/clang/lib/Sema/SemaConcept.cpp
@@ -1002,6 +1002,7 @@
     S.DiagnoseUnsatisfiedConstraint(CSE->getSatisfaction());
     return;
   } else if (auto *RE = dyn_cast<RequiresExpr>(SubstExpr)) {
+    // TODO(usx): Store and diagnose dependent diagnositcs here.
     for (concepts::Requirement *Req : RE->getRequirements())
       if (!Req->isDependent() && !Req->isSatisfied()) {
         if (auto *E = dyn_cast<concepts::ExprRequirement>(Req))
diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -15,6 +15,7 @@
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/ASTLambda.h"
 #include "clang/AST/ASTMutationListener.h"
+#include "clang/AST/DeclBase.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/Expr.h"
 #include "clang/AST/ExprConcepts.h"
@@ -1363,7 +1364,17 @@
 
     ExprResult TransformRequiresExpr(RequiresExpr *E) {
       LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
-      return inherited::TransformRequiresExpr(E);
+      auto TransReq = inherited::TransformRequiresExpr(E);
+      if (E->getBody()->isDependentContext()) {
+        Sema::SFINAETrap Trap(SemaRef);
+        // We recreate the RequiresExpr body, but not by instantiating it.
+        // Produce pending diagnostics for dependent access check.
+        SemaRef.PerformDependentDiagnostics(E->getBody(), TemplateArgs);
+        // TODO(usx): Store SFINAE diagnostics in RequiresExpr for diagnosis.
+        if (Trap.hasErrorOccurred())
+          TransReq.getAs<RequiresExpr>()->setSatisfied(false);
+      }
+      return TransReq;
     }
 
     bool TransformRequiresExprRequirements(
diff --git a/clang/test/CXX/expr/expr.prim/expr.prim.req/simple-requirement.cpp b/clang/test/CXX/expr/expr.prim/expr.prim.req/simple-requirement.cpp
--- a/clang/test/CXX/expr/expr.prim/expr.prim.req/simple-requirement.cpp
+++ b/clang/test/CXX/expr/expr.prim/expr.prim.req/simple-requirement.cpp
@@ -104,3 +104,138 @@
 constexpr bool b = requires (X &x) { static_cast<int(*)[(typeid(x), 0)]>(nullptr); };
 // expected-error@-1{{constraint variable 'x' cannot be used in an evaluated context}}
 // expected-note@-2{{'x' declared here}}
+
+namespace access_checks {
+namespace in_requires_expression {
+template<auto>
+struct A {
+    static constexpr bool foo();
+    static constexpr bool bar();
+    static constexpr bool baz();
+    static constexpr bool faz();
+};
+
+class C{};
+
+class B {
+    void p() {}
+    bool data_member = true;
+    static const bool static_member = true;
+    friend struct A<0>;
+};
+
+template<auto x>
+constexpr bool A<x>::foo() {
+    return requires(B b) { b.p(); };
+}
+static_assert(!A<1>::foo());
+static_assert(A<0>::foo());
+
+template<auto x>
+constexpr bool A<x>::bar() {
+    return requires() { B::static_member; };
+}
+static_assert(!A<1>::bar());
+static_assert(A<0>::bar());
+
+template<auto x>
+constexpr bool A<x>::baz() {
+    return requires(B b) { b.data_member; };
+}
+static_assert(!A<1>::baz());
+static_assert(A<0>::baz());
+
+template<auto x>
+constexpr bool A<x>::faz() {
+    return requires(B a, B b) { 
+      a.p();
+      b.data_member;
+      B::static_member;
+    };
+}
+static_assert(!A<1>::faz());
+static_assert(A<0>::faz());
+} // namespace in_requires_expression
+
+namespace in_concepts {
+// Dependent access does not cause hard errors.
+template<int N> class A;
+
+template <> class A<0> {
+  static void f() {}
+};
+template<int N>
+concept C1 = requires() { A<N>::f(); };
+static_assert(!C1<0>);
+
+template <> class A<1> {
+public: 
+  static void f() {}
+};
+static_assert(C1<1>);
+
+// Non-dependent access to private member is a hard error.
+class B{
+   static void f() {} // expected-note 2{{implicitly declared private here}}
+};
+template<class T>
+concept C2 = requires() { B::f(); }; // expected-error {{'f' is a private member}}
+
+constexpr bool non_template_func() {
+  return requires() {
+      B::f(); // expected-error {{'f' is a private member}}
+  };
+}
+template<int x>
+constexpr bool template_func() {
+  return requires() {
+      A<x>::f();
+  };
+}
+static_assert(!template_func<0>());
+static_assert(template_func<1>());
+} // namespace in_concepts
+
+namespace in_trailing_requires {
+template <class> struct B;
+class A {
+   static void f();
+   friend struct B<short>;
+};
+ 
+template <class T> struct B {
+  static constexpr int index() requires requires{ A::f(); } {
+    return 1;
+  }
+  static constexpr int index() {
+    return 2;
+  }
+};
+
+static_assert(B<short>::index() == 1);
+static_assert(B<int>::index() == 2);
+
+namespace missing_member_function {
+template <class T> struct Use;
+class X { 
+  int a;
+  static int B;
+  friend struct Use<short>;
+};
+template <class T> struct Use {
+  constexpr static int foo() requires requires(X x) { x.a; } {
+    return 1;
+  }
+  constexpr static int bar() requires requires { X::B; } {
+    return 1;
+  }
+};
+
+void test() {
+  // TODO: Propagate diagnostic.
+  Use<int>::foo(); //expected-error {{invalid reference to function 'foo': constraints not satisfied}}
+  static_assert(Use<short>::foo() == 1);
+}
+} // namespace missing_member_function
+} // namespace in_trailing_requires
+} // namespace access_check