Index: clang-tools-extra/clang-tidy/misc/ConfusableIdentifierCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/misc/ConfusableIdentifierCheck.cpp
+++ clang-tools-extra/clang-tidy/misc/ConfusableIdentifierCheck.cpp
@@ -99,10 +99,9 @@
     if (IdentifierInfo *II = ND->getIdentifier()) {
       StringRef NDName = II->getName();
       llvm::SmallVector<const NamedDecl *> &Mapped = Mapper[skeleton(NDName)];
-      const DeclContext *NDDecl = ND->getDeclContext();
       for (const NamedDecl *OND : Mapped) {
-        if (!NDDecl->isDeclInLexicalTraversal(OND) &&
-            !OND->getDeclContext()->isDeclInLexicalTraversal(ND))
+        if (!ND->getDeclContext()->Encloses(OND->getDeclContext()) &&
+            !OND->getDeclContext()->Encloses(ND->getDeclContext()))
           continue;
         if (OND->getIdentifier()->getName() != NDName) {
           diag(OND->getLocation(), "%0 is confusable with %1")
Index: clang-tools-extra/test/clang-tidy/checkers/misc/confusable-identifiers.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/checkers/misc/confusable-identifiers.cpp
+++ clang-tools-extra/test/clang-tidy/checkers/misc/confusable-identifiers.cpp
@@ -18,8 +18,26 @@
 int fi;
 // CHECK-MESSAGES: :[[#@LINE-1]]:5: note: other declaration found here
 
+bool f0(const char *q1, const char *ql) {
+  // CHECK-MESSAGES: :[[#@LINE-1]]:21: warning: q1 is confusable with ql [misc-confusable-identifiers]
+  // CHECK-MESSAGES: :[[#@LINE-2]]:37: note: other declaration found here
+  return q1 < ql;
+}
+
 // should not print anything
 namespace ns {
 struct Foo {};
 } // namespace ns
 auto f = ns::Foo();
+
+struct Test {
+  void f1(const char *pl);
+};
+
+bool f2(const char *p1, const char *ql) {
+  return p1 < ql;
+}
+
+bool f3(const char *q0, const char *q1) {
+  return q0 < q1;
+}