diff --git a/lldb/include/lldb/Symbol/SymbolFile.h b/lldb/include/lldb/Symbol/SymbolFile.h
--- a/lldb/include/lldb/Symbol/SymbolFile.h
+++ b/lldb/include/lldb/Symbol/SymbolFile.h
@@ -331,6 +331,12 @@
     return CompilerDeclContext();
   }
 
+  virtual CompilerDeclContext
+  FindNamespace(ConstString name, const CompilerDeclContext &parent_decl_ctx,
+                bool only_root_namespaces) {
+    return CompilerDeclContext();
+  }
+
   virtual ObjectFile *GetObjectFile() = 0;
   virtual const ObjectFile *GetObjectFile() const = 0;
   virtual ObjectFile *GetMainObjectFile() = 0;
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
@@ -700,7 +700,8 @@
     if (!symbol_file)
       continue;
 
-    found_namespace_decl = symbol_file->FindNamespace(name, namespace_decl);
+    found_namespace_decl =
+        symbol_file->FindNamespace(name, namespace_decl, true);
 
     if (found_namespace_decl) {
       context.m_namespace_map->push_back(
@@ -1674,7 +1675,7 @@
         continue;
 
       found_namespace_decl =
-          symbol_file->FindNamespace(name, null_namespace_decl);
+          symbol_file->FindNamespace(name, null_namespace_decl, true);
 
       if (!found_namespace_decl)
         continue;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
@@ -218,6 +218,11 @@
       lldb_private::ConstString name,
       const lldb_private::CompilerDeclContext &parent_decl_ctx) override;
 
+  lldb_private::CompilerDeclContext
+  FindNamespace(lldb_private::ConstString name,
+                const lldb_private::CompilerDeclContext &parent_decl_ctx,
+                bool only_root_namespaces) override;
+
   void PreloadSymbols() override;
 
   std::recursive_mutex &GetModuleMutex() const override;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -2633,6 +2633,13 @@
 CompilerDeclContext
 SymbolFileDWARF::FindNamespace(ConstString name,
                                const CompilerDeclContext &parent_decl_ctx) {
+  return FindNamespace(name, parent_decl_ctx, false);
+}
+
+CompilerDeclContext
+SymbolFileDWARF::FindNamespace(ConstString name,
+                               const CompilerDeclContext &parent_decl_ctx,
+                               bool only_root_namespaces) {
   std::lock_guard<std::recursive_mutex> guard(GetModuleMutex());
   Log *log = GetLog(DWARFLog::Lookups);
 
@@ -2648,6 +2655,11 @@
     return namespace_decl_ctx;
 
   m_index->GetNamespaces(name, [&](DWARFDIE die) {
+    // We want only root namespaces.
+    if (only_root_namespaces &&
+        die.GetParent().Tag() != dwarf::DW_TAG_compile_unit && !parent_decl_ctx)
+      return true;
+
     if (!DIEInDeclContext(parent_decl_ctx, die))
       return true; // The containing decl contexts don't match
 
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h
@@ -139,6 +139,10 @@
   lldb_private::CompilerDeclContext FindNamespace(
       lldb_private::ConstString name,
       const lldb_private::CompilerDeclContext &parent_decl_ctx) override;
+  lldb_private::CompilerDeclContext
+  FindNamespace(lldb_private::ConstString name,
+                const lldb_private::CompilerDeclContext &parent_decl_ctx,
+                bool only_root_namespaces) override;
   void GetTypes(lldb_private::SymbolContextScope *sc_scope,
                 lldb::TypeClass type_mask,
                 lldb_private::TypeList &type_list) override;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
@@ -1258,11 +1258,18 @@
 CompilerDeclContext SymbolFileDWARFDebugMap::FindNamespace(
     lldb_private::ConstString name,
     const CompilerDeclContext &parent_decl_ctx) {
+  return FindNamespace(name, parent_decl_ctx, false);
+}
+
+CompilerDeclContext SymbolFileDWARFDebugMap::FindNamespace(
+    lldb_private::ConstString name, const CompilerDeclContext &parent_decl_ctx,
+    bool only_root_namespaces) {
   std::lock_guard<std::recursive_mutex> guard(GetModuleMutex());
   CompilerDeclContext matching_namespace;
 
   ForEachSymbolFile([&](SymbolFileDWARF *oso_dwarf) -> bool {
-    matching_namespace = oso_dwarf->FindNamespace(name, parent_decl_ctx);
+    matching_namespace =
+        oso_dwarf->FindNamespace(name, parent_decl_ctx, only_root_namespaces);
 
     return (bool)matching_namespace;
   });
diff --git a/lldb/test/API/commands/expression/inline-namespace/TestInlineNamespace.py b/lldb/test/API/commands/expression/inline-namespace/TestInlineNamespace.py
--- a/lldb/test/API/commands/expression/inline-namespace/TestInlineNamespace.py
+++ b/lldb/test/API/commands/expression/inline-namespace/TestInlineNamespace.py
@@ -46,7 +46,7 @@
 
         self.expect("expr A::other_var", error=True, substrs=["no member named 'other_var' in namespace 'A'"])
         self.expect("expr A::B::other_var", error=True, substrs=["no member named 'other_var' in namespace 'A::B'"])
-        self.expect("expr B::other_var", error=True, substrs=["no member named 'other_var' in namespace 'A::B'"])
+        self.expect("expr B::other_var", error=True, substrs=["use of undeclared identifier 'B'"])
 
         # 'frame variable' can correctly distinguish between A::B::global_var and A::global_var
         gvars = self.target().FindGlobalVariables("A::global_var", 10)
diff --git a/lldb/test/API/lang/cpp/namespace/TestNamespace.py b/lldb/test/API/lang/cpp/namespace/TestNamespace.py
--- a/lldb/test/API/lang/cpp/namespace/TestNamespace.py
+++ b/lldb/test/API/lang/cpp/namespace/TestNamespace.py
@@ -23,7 +23,8 @@
             "func(int)",
             "A::B::func()",
             "A::func()",
-            "A::func(int)"]
+            "A::func(int)",
+            "B::func()"]
 
         # Create a target by the debugger.
         exe = self.getBuildArtifact("a.out")
@@ -225,3 +226,6 @@
 
         self.expect("expression variadic_sum", patterns=[
                     '\(anonymous namespace\)::variadic_sum\(int, ...\)'])
+
+        self.expect_expr("::B::Bar b; b.x()", result_type="int", result_value="42")
+        self.expect_expr("A::B::Bar b; b.y()", result_type="int", result_value="137")
diff --git a/lldb/test/API/lang/cpp/namespace/main.cpp b/lldb/test/API/lang/cpp/namespace/main.cpp
--- a/lldb/test/API/lang/cpp/namespace/main.cpp
+++ b/lldb/test/API/lang/cpp/namespace/main.cpp
@@ -102,6 +102,18 @@
     return myfunc2(3) + j + i + a + 2 + anon_uint + a_uint + b_uint + y_uint; // Set break point at this line.
 }
 
+namespace B {
+struct Bar {
+    int x() { return 42; }
+};
+} // namespace B
+
+namespace A::B {
+struct Bar {
+    int y() { return 137; }
+};
+} // namespace A::B
+
 int
 main (int argc, char const *argv[])
 {
@@ -112,5 +124,7 @@
     A::B::test_lookup_at_nested_ns_scope_after_using();
     test_lookup_before_using_directive();
     test_lookup_after_using_directive();
-    return Foo::myfunc(12);
+    ::B::Bar bb;
+    A::B::Bar ab;
+    return Foo::myfunc(12) + bb.x() + ab.y();
 }
diff --git a/lldb/test/API/lang/cpp/namespace/ns.cpp b/lldb/test/API/lang/cpp/namespace/ns.cpp
--- a/lldb/test/API/lang/cpp/namespace/ns.cpp
+++ b/lldb/test/API/lang/cpp/namespace/ns.cpp
@@ -21,3 +21,7 @@
   std::printf("at global scope: foo() = %d\n", foo()); // eval foo(), exp: 42
   std::printf("at global scope: func() = %d\n", func()); // eval func(), exp: 1
 }
+
+namespace B {
+int func() { return 4; }
+} // namespace B