[clang] [llvm] [HLSL] Add type traits for ConstantBuffers templates (PR #195154)

[Steven Perron via cfe-commits]

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@@ -20,6 +20,39 @@ union U {
 ConstantBuffer<S> cb;
 ConstantBuffer<Empty> cb_empty;
 
+// Invalid: non-struct/class
+// expected-error at +1 {{constraints not satisfied for class template 'ConstantBuffer'}}
+ConstantBuffer<float> cb_float;
+// expected-note@* {{because 'float' does not satisfy '__is_constant_buffer_element_compatible'}}
+// expected-note@* {{because '__builtin_hlsl_is_constant_buffer_element_compatible(float)' evaluated to false}}
+
+// expected-error at +1 {{constraints not satisfied for class template 'ConstantBuffer'}}
+ConstantBuffer<float4> cb_float4;
+// expected-note@* {{because 'float4' (aka 'vector<float, 4>') does not satisfy '__is_constant_buffer_element_compatible'}}
+// expected-note@* {{because '__builtin_hlsl_is_constant_buffer_element_compatible(vector<float, 4>)' evaluated to false}}
+
+// expected-error at +1 {{constraints not satisfied for class template 'ConstantBuffer'}}
+ConstantBuffer<float[4]> cb_array;
+// expected-note@* {{because 'float[4]' does not satisfy '__is_constant_buffer_element_compatible'}}
+// expected-note@* {{because '__builtin_hlsl_is_constant_buffer_element_compatible(float[4])' evaluated to false}}
+
+// Invalid: contains resource
+// expected-error at +1 {{constraints not satisfied for class template 'ConstantBuffer'}}
+ConstantBuffer<ContainsResource> cb_res;
+// expected-note@* {{because 'ContainsResource' does not satisfy '__is_constant_buffer_element_compatible'}}
+// expected-note@* {{because '__builtin_hlsl_is_constant_buffer_element_compatible(ContainsResource)' evaluated to false}}
+
+// Invalid: intangible type
+// expected-error at +1 {{use of class template 'Texture2D' requires template arguments}}
+ConstantBuffer<Texture2D> cb_tex;
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s-perron wrote:

I added that as a separate test. The error messages are not great, but, I want to make sure ConstantBuffer<Texture2D> fails as well.

https://github.com/llvm/llvm-project/pull/195154