spirv-opt: CombineAccessChains doesn't support identical pointer types

[Vasniktel]

data.zip

               OpCapability Shader
          %1 = OpExtInstImport "GLSL.std.450"
               OpMemoryModel Logical GLSL450
               OpEntryPoint Fragment %4 "main" %9
               OpExecutionMode %4 OriginUpperLeft
               OpSource ESSL 320
          %2 = OpTypeVoid
          %3 = OpTypeFunction %2
          %6 = OpTypeInt 32 1
         %12 = OpTypeVector %6 2
         %14 = OpConstant %6 1
         %13 = OpConstantComposite %12 %14 %14
          %7 = OpTypePointer Private %6
          %8 = OpTypePointer Private %6
         %15 = OpTypePointer Private %12
          %9 = OpVariable %15 Private %13
          %4 = OpFunction %2 None %3
          %5 = OpLabel
         %10 = OpAccessChain %7 %9 %14
         %11 = OpAccessChain %8 %10
               OpReturn
               OpFunctionEnd

spirv-opt produces the following error

error: line 20: Expected Result Type and Operand type to be the same
%11 = OpCopyObject %_ptr_Private_int_0 %10

error: line 0: Validation failed after pass combine-access-chains

if executed with the following command spirv-opt <attached shader> -o out.spv --validate-after-all --combine-access-chains.

Can be reproduced on c20995e.

[Vasniktel]

@s-perron @alan-baker ping.

[Vasniktel]

Persists on 69f07da.