diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -194,6 +194,9 @@
 - Fix crash when evaluating consteval constructor of derived class whose base
   has more than one field.
   (`#60166 <https://github.com/llvm/llvm-project/issues/60166>`_)
+- Fix an issue about ``decltype`` in the members of class templates derived from
+  templates with related parameters.
+  (`#58674 <https://github.com/llvm/llvm-project/issues/58674>`_)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -2803,6 +2803,21 @@
     R.addDecl(FoundDecl);
     R.resolveKind();
 
+    if (getSema().isUnevaluatedContext() && Base->isImplicitCXXThis() &&
+        isa<FieldDecl, IndirectFieldDecl, MSPropertyDecl>(Member)) {
+      if (auto ThisClass = cast<CXXThisExpr>(Base)
+                               ->getType()
+                               ->getPointeeType()
+                               ->getAsCXXRecordDecl()) {
+        auto Class = cast<CXXRecordDecl>(Member->getDeclContext());
+        // In unevaluated contexts, an expression supposed to be a member access
+        // might reference a member in an unrelated class.
+        if (!ThisClass->Equals(Class) && !ThisClass->isDerivedFrom(Class))
+          return getSema().BuildDeclRefExpr(Member, Member->getType(),
+                                            VK_LValue, Member->getLocation());
+      }
+    }
+
     return getSema().BuildMemberReferenceExpr(Base, BaseType, OpLoc, isArrow,
                                               SS, TemplateKWLoc,
                                               FirstQualifierInScope,
diff --git a/clang/test/CodeGenCXX/decl-ref-inheritance.cpp b/clang/test/CodeGenCXX/decl-ref-inheritance.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGenCXX/decl-ref-inheritance.cpp
@@ -0,0 +1,60 @@
+// RUN: %clang_cc1 -triple=x86_64-unknown-linux -emit-llvm %s -o - | FileCheck \
+// RUN: -check-prefix=CHECK-1 %s
+// RUN: %clang_cc1 -triple=x86_64-unknown-linux -emit-llvm %s -o - | FileCheck \
+// RUN: -check-prefix=CHECK-2 %s
+// RUN: %clang_cc1 -triple=x86_64-unknown-linux -emit-llvm %s -o - | FileCheck \
+// RUN: -check-prefix=CHECK-3 %s
+
+// CHECK-1: [[FOO:%.+]] = type { float }
+struct foo {
+  float val;
+};
+
+template <typename T> struct bar : T {
+};
+
+struct baz : bar<foo> {
+  // CHECK-1: define{{.*}} float @_ZN3baz3getEv
+  // CHECK-1: {{%.+}} = getelementptr inbounds [[FOO]], ptr {{%.+}}, i32 0, i32 0
+  float get() {
+    return val;
+  }
+};
+
+int qux() {
+  auto f = baz{};
+  return f.get();
+}
+
+// CHECK-2: [[F:%.+]] = type { ptr }
+struct f {
+  void *g;
+};
+
+template <typename j> struct k : j {
+  // CHECK-2: define{{.*}} void @_ZN1kI1fE1lEv
+  // CHECK-2: {{%.+}} = getelementptr inbounds [[F]], ptr {{%.+}}, i32 0, i32 0
+  virtual void l(){ (void)f::g; }
+};
+
+k<f> q;
+
+// CHECK-3: [[BASE:%.+]] = type { i32 }
+class Base {
+protected:
+  int member;
+};
+
+template <typename Parent>
+struct Subclass : public Parent {
+  // CHECK-3: define{{.*}} i32 @_ZN8SubclassI4BaseE4funcEv
+  // CHECK-3: {{%.+}} = getelementptr inbounds [[BASE]], ptr {{%.+}}, i32 0, i32 0
+  int func() { return Base::member; }
+};
+
+using Impl = Subclass<Base>;
+
+int use() {
+  Impl i;
+  return i.func();
+}
diff --git a/clang/test/SemaCXX/decltype.cpp b/clang/test/SemaCXX/decltype.cpp
--- a/clang/test/SemaCXX/decltype.cpp
+++ b/clang/test/SemaCXX/decltype.cpp
@@ -101,6 +101,44 @@
   template<class T> void foo(decltype(T(LP1{ .p1 = g1, .p1.x[1] = 'x' }))) {}
 }
 
+namespace GH58674 {
+  struct Foo {
+    float value_;
+    struct nested {
+      float value_;
+    };
+  };
+
+  template <typename T>
+  struct TemplateFoo {
+    float value_;
+  };
+
+  float bar;
+
+  template <typename T>
+  struct Animal{};
+
+  template <typename T>
+  class Cat : Animal<T> {
+    using okay = decltype(Foo::value_);
+    using also_okay = decltype(bar);
+    using okay2 = decltype(Foo::nested::value_);
+    using okay3 = decltype(TemplateFoo<T>::value_);
+  public:
+    void meow() {
+      using okay = decltype(Foo::value_);
+      using also_okay = decltype(bar);
+      using okay2 = decltype(Foo::nested::value_);
+      using okay3 = decltype(TemplateFoo<T>::value_);
+    }
+  };
+
+  void baz() {
+      Cat<void>{}.meow();
+  }
+}
+
 template<typename>
 class conditional {
 };