diff --git a/clang-tools-extra/clangd/InlayHints.cpp b/clang-tools-extra/clangd/InlayHints.cpp
--- a/clang-tools-extra/clangd/InlayHints.cpp
+++ b/clang-tools-extra/clangd/InlayHints.cpp
@@ -663,7 +663,14 @@
   }
 
   void addTypeHint(SourceRange R, QualType T, llvm::StringRef Prefix) {
+    // print the underlying type for `decltype(expr)`
+    if (T->isDecltypeType())
+      TypeHintPolicy.PrintCanonicalTypes = true;
+    else if (const AutoType *AT = T->getContainedAutoType();
+             AT && AT->getDeducedType()->isDecltypeType())
+      TypeHintPolicy.PrintCanonicalTypes = true;
     addTypeHint(R, T, Prefix, TypeHintPolicy);
+    TypeHintPolicy.PrintCanonicalTypes = false;
   }
 
   void addTypeHint(SourceRange R, QualType T, llvm::StringRef Prefix,
diff --git a/clang-tools-extra/clangd/unittests/InlayHintTests.cpp b/clang-tools-extra/clangd/unittests/InlayHintTests.cpp
--- a/clang-tools-extra/clangd/unittests/InlayHintTests.cpp
+++ b/clang-tools-extra/clangd/unittests/InlayHintTests.cpp
@@ -1364,7 +1364,6 @@
 TEST(TypeHints, Decltype) {
   assertTypeHints(R"cpp(
     $a[[decltype(0)]] a;
-    // FIXME: will be nice to show `: int` instead
     $b[[decltype(a)]] b;
     const $c[[decltype(0)]] &c = b;
 
@@ -1377,11 +1376,13 @@
 
     template <class, class> struct Foo;
     using G = Foo<$g[[decltype(0)]], float>;
+
+    auto $h[[h]] = $i[[decltype(0)]]{};
   )cpp",
-                  ExpectedHint{": int", "a"},
-                  ExpectedHint{": decltype(0)", "b"},
+                  ExpectedHint{": int", "a"}, ExpectedHint{": int", "b"},
                   ExpectedHint{": int", "c"}, ExpectedHint{": int", "e"},
-                  ExpectedHint{": int", "f"}, ExpectedHint{": int", "g"});
+                  ExpectedHint{": int", "f"}, ExpectedHint{": int", "g"},
+                  ExpectedHint{": int", "h"}, ExpectedHint{": int", "i"});
 }
 
 TEST(DesignatorHints, Basic) {