diff --git a/include/swift/AST/DiagnosticsSIL.def b/include/swift/AST/DiagnosticsSIL.def
index acea284180310..d24955141f5b1 100644
--- a/include/swift/AST/DiagnosticsSIL.def
+++ b/include/swift/AST/DiagnosticsSIL.def
@@ -396,9 +396,6 @@ NOTE(autodiff_protocol_member_not_differentiable,none,
 NOTE(autodiff_protocol_member_subset_indices_not_differentiable,none,
      "member is differentiable only with respect to a smaller subset of "
      "arguments", ())
-NOTE(autodiff_function_subset_indices_not_differentiable,none,
-     "function is differentiable only with respect to a smaller subset of "
-     "arguments", ())
 NOTE(autodiff_function_assoc_func_requirements_unmet,none,
      "function call is not differentiable because generic requirements are not "
      "met", ())
diff --git a/lib/SILOptimizer/Mandatory/Differentiation.cpp b/lib/SILOptimizer/Mandatory/Differentiation.cpp
index fedac4c75cba9..c7e17179579ad 100644
--- a/lib/SILOptimizer/Mandatory/Differentiation.cpp
+++ b/lib/SILOptimizer/Mandatory/Differentiation.cpp
@@ -1793,13 +1793,6 @@ emitAssociatedFunctionReference(ADContext &context, SILBuilder &builder,
     if (autodiffFnType->isDifferentiable()) {
       SILValue assocFn = builder.createAutoDiffFunctionExtract(
           original.getLoc(), kind, /*differentiationOrder*/ 1, functionSource);
-      if (autodiffFnType->getDifferentiationParameterIndices().test(
-              desiredIndices.parameters)) {
-        context.emitNondifferentiabilityError(
-            original, parentTask,
-            diag::autodiff_function_subset_indices_not_differentiable);
-        return None;
-      }
       SILAutoDiffIndices indices(0, desiredIndices.parameters);
       return std::make_pair(assocFn, indices);
     }
diff --git a/test/AutoDiff/simple_math.swift b/test/AutoDiff/simple_math.swift
index 63e6a751e1da7..a202b9fb5699a 100644
--- a/test/AutoDiff/simple_math.swift
+++ b/test/AutoDiff/simple_math.swift
@@ -308,4 +308,12 @@ SimpleMathTests.test("StructGeneric") {
   expectEqual(405, gradient(at: 3, in: fifthPower))
 }
 
+SimpleMathTests.test("SubsetIndices") {
+  func train(_ lossFunction: @differentiable (Float, Float) -> Float) {
+    let y = Float(0)
+    _ = gradient(at: 0) { x in lossFunction(x, y) }
+  }
+  train { x, y in x + y }
+}
+
 runAllTests()