diff --git a/xls/dslx/type_system/deduce.cc b/xls/dslx/type_system/deduce.cc
index 4991498589..2f1f913bcb 100644
--- a/xls/dslx/type_system/deduce.cc
+++ b/xls/dslx/type_system/deduce.cc
@@ -2079,14 +2079,24 @@ class DeduceVisitor : public AstNodeVisitor {
     return Fatal(n);
   }
   absl::Status HandleFunctionRef(const FunctionRef* n) override {
-    return Fatal(n);
+    XLS_ASSIGN_OR_RETURN(std::unique_ptr<Type> callee_type,
+                         ctx_->Deduce(n->callee()));
+    if (!callee_type->IsFunction()) {
+      return TypeInferenceErrorStatus(
+          n->span(), callee_type.get(),
+          "Callee for function reference must be function-typed",
+          ctx_->file_table());
+    }
+    result_ = std::move(callee_type);
+    return absl::OkStatus();
   }
 
   absl::StatusOr<std::unique_ptr<Type>>& result() { return result_; }
 
  private:
   absl::Status Fatal(const AstNode* n) {
-    LOG(FATAL) << "Got unhandled AST node for deduction: " << n->ToString();
+    LOG(FATAL) << "DeduceVisitor got unhandled AST node for deduction: "
+               << n->ToString() << " node type name: " << n->GetNodeTypeName();
   }
 
   DeduceCtx* ctx_;
diff --git a/xls/dslx/type_system/type.cc b/xls/dslx/type_system/type.cc
index c4fecb9e52..7d3daec657 100644
--- a/xls/dslx/type_system/type.cc
+++ b/xls/dslx/type_system/type.cc
@@ -431,6 +431,10 @@ bool Type::IsTuple() const {
   return dynamic_cast<const TupleType*>(this) != nullptr;
 }
 
+bool Type::IsFunction() const {
+  return dynamic_cast<const FunctionType*>(this) != nullptr;
+}
+
 const EnumType& Type::AsEnum() const {
   auto* s = dynamic_cast<const EnumType*>(this);
   CHECK(s != nullptr) << "Type is not an enum: " << *this;
diff --git a/xls/dslx/type_system/type.h b/xls/dslx/type_system/type.h
index 79a21473e9..01f183945a 100644
--- a/xls/dslx/type_system/type.h
+++ b/xls/dslx/type_system/type.h
@@ -398,6 +398,7 @@ class Type {
   bool IsArray() const;
   bool IsMeta() const;
   bool IsTuple() const;
+  bool IsFunction() const;
 
   const StructType& AsStruct() const;
   const ProcType& AsProc() const;
diff --git a/xls/dslx/type_system/typecheck_module_test.cc b/xls/dslx/type_system/typecheck_module_test.cc
index 1bef09f3c0..4d5bfa9726 100644
--- a/xls/dslx/type_system/typecheck_module_test.cc
+++ b/xls/dslx/type_system/typecheck_module_test.cc
@@ -3884,6 +3884,14 @@ proc t {
 )"));
 }
 
+TEST(TypecheckErrorTest, InstantiateALiteralNumber) {
+  constexpr std::string_view kProgram = "fn f(x:u2) { 0<> }";
+  EXPECT_THAT(Typecheck(kProgram).status(),
+              IsPosError("TypeInferenceError",
+                         HasSubstr("Could not infer a type for this number, "
+                                   "please annotate a type.")));
+}
+
 TEST(TypecheckErrorTest, SignedValueToBuiltinExpectingUNViaParametric) {
   EXPECT_THAT(Typecheck(R"(
 fn p<S: bool, N: u32>() -> u32 {