diff --git a/clang-tools-extra/clangd/index/CanonicalIncludes.cpp b/clang-tools-extra/clangd/index/CanonicalIncludes.cpp
--- a/clang-tools-extra/clangd/index/CanonicalIncludes.cpp
+++ b/clang-tools-extra/clangd/index/CanonicalIncludes.cpp
@@ -88,16 +88,6 @@
 
 void addSystemHeadersMapping(CanonicalIncludes *Includes) {
   static const std::vector<std::pair<const char *, const char *>> SymbolMap = {
-      // Map symbols in <iosfwd> to their preferred includes.
-      {"std::basic_filebuf", "<fstream>"},
-      {"std::filebuf", "<fstream>"},
-      {"std::wfilebuf", "<fstream>"},
-      {"std::basic_istream", "<istream>"},
-      {"std::istream", "<istream>"},
-      {"std::wistream", "<istream>"},
-      {"std::basic_ostream", "<ostream>"},
-      {"std::ostream", "<ostream>"},
-      {"std::wostream", "<ostream>"},
       {"std::uint_least16_t", "<cstdint>"}, // <type_traits> redeclares these
       {"std::uint_least32_t", "<cstdint>"},
 #define SYMBOL(Name, NameSpace, Header) { #NameSpace#Name, #Header },
@@ -110,8 +100,6 @@
   // FIXME: remove the std header mapping once we support ambiguous symbols, now
   // it serves as a fallback to disambiguate:
   //   - symbols with mulitiple headers (e.g. std::move)
-  //   - symbols with a primary template in one header and a specialization in
-  //     another (std::abs)
   static const std::vector<std::pair<const char *, const char *>>
       SystemHeaderMap = {
           {"include/__stddef_max_align_t.h", "<cstddef>"},