[HLSL] Declaring in/out variables in global scope triggers unhelpful assertion

[rdb]

Running this:

glslangValidator -e main -G test.vert.hlsl

With this shader code:

out float4 l_position : SV_Position;

void main() {
    l_position = float4(0, 0, 0, 0);
}

Triggers an assert(false):

glslangValidator: ../SPIRV/GlslangToSpv.cpp:1233: spv::StorageClass {anonymous}::TGlslangToSpvTraverser::TranslateStorageClass(const glslang::TType&): Assertion `0' failed.

It would be more helpful to show an appropriate error message. For example, DXC shows this:

test.vert.hlsl:1:1: error: HLSL usage 'out' is only valid on a parameter
out float4 l_position : SV_Position;
^~~