From a81efa750f093fdbfcf28c5d9bd619fca119bcde Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Tue, 16 Apr 2019 07:46:02 -0700
Subject: Add the missing case for `AssocTypeDecl` in varying parameters'
 layout generation. (#947)

---
 source/slang/parameter-binding.cpp                 |   6 ++
 source/slang/type-layout.cpp                       |   7 ++
 tests/compute/type-param-varying.slang             | 107 +++++++++++++++++++++
 .../compute/type-param-varying.slang.expected.txt  |   1 +
 4 files changed, 121 insertions(+)
 create mode 100644 tests/compute/type-param-varying.slang
 create mode 100644 tests/compute/type-param-varying.slang.expected.txt

diff --git a/source/slang/parameter-binding.cpp b/source/slang/parameter-binding.cpp
index caab5ce6e..293a24338 100644
--- a/source/slang/parameter-binding.cpp
+++ b/source/slang/parameter-binding.cpp
@@ -1736,6 +1736,12 @@ static RefPtr<TypeLayout> processEntryPointVaryingParameter(
             genParamTypeLayout->findOrAddResourceInfo(LayoutResourceKind::GenericResource)->count += 1;
             return genParamTypeLayout;
         }
+        else if (auto associatedTypeParam = declRef.as<AssocTypeDecl>())
+        {
+            RefPtr<TypeLayout> assocTypeLayout = new TypeLayout();
+            assocTypeLayout->type = type;
+            return assocTypeLayout;
+        }
         else
         {
             SLANG_UNEXPECTED("unhandled type kind");
diff --git a/source/slang/type-layout.cpp b/source/slang/type-layout.cpp
index ce767fc8b..90acf0d3c 100644
--- a/source/slang/type-layout.cpp
+++ b/source/slang/type-layout.cpp
@@ -2784,6 +2784,13 @@ static TypeLayoutResult _createTypeLayout(
 
             return TypeLayoutResult(genParamTypeLayout, info);
         }
+        else if (auto assocTypeParam = declRef.as<AssocTypeDecl>())
+        {
+            return createSimpleTypeLayout(
+                SimpleLayoutInfo(),
+                type,
+                rules);
+        }
         else if( auto simpleGenericParam = declRef.as<GenericTypeParamDecl>() )
         {
             // A bare generic type parameter can come up during layout
diff --git a/tests/compute/type-param-varying.slang b/tests/compute/type-param-varying.slang
new file mode 100644
index 000000000..ef9ae9881
--- /dev/null
+++ b/tests/compute/type-param-varying.slang
@@ -0,0 +1,107 @@
+//TEST(compute):COMPARE_RENDER_COMPUTE:
+
+//TEST_INPUT: global_type AssembledVertex
+//TEST_INPUT: ubuffer(data=[0], stride=4):dxbinding(1),glbinding(0),out
+
+// Testing associated types in a varying parameter field
+
+interface IColorSet
+{
+    float3 getColor();
+}
+
+struct NoColorSet : IColorSet
+{
+    float3 getColor() { return float3(0.0); }
+};
+
+struct SingleColorSet : IColorSet
+{
+    float3 color;
+    float3 getColor() { return color; }
+};
+
+interface IVertexFormat
+{
+    associatedtype ColorSet : IColorSet;
+    ColorSet getColorSet();
+    float3 getPosition();
+    float2 getUv();
+}
+
+type_param TVertex : IVertexFormat;
+
+cbuffer Uniforms
+{
+    float4x4 modelViewProjection;
+}
+RWStructuredBuffer<float> outputBuffer;
+
+struct AssembledVertex : IVertexFormat
+{
+    typedef SingleColorSet ColorSet;
+    float3	position;
+    SingleColorSet	colorSet;
+    float2  uv;
+    ColorSet getColorSet() { return colorSet; }
+    float3 getPosition() { return position; }
+    float2 getUv() { return uv; }
+};
+
+struct CoarseVertex
+{
+    TVertex.ColorSet	color;
+    float2  uv;
+};
+
+struct Fragment
+{
+    float4 color;
+};
+
+
+// Vertex  Shader
+
+struct VertexStageInput
+{
+    TVertex assembledVertex	: A;
+};
+
+struct VertexStageOutput
+{
+    CoarseVertex	coarseVertex	: CoarseVertex;
+    float4			sv_position		: SV_Position;
+};
+
+VertexStageOutput vertexMain(VertexStageInput input)
+{
+    VertexStageOutput output;
+
+    float3 position = input.assembledVertex.getPosition();
+    output.sv_position = mul(modelViewProjection, float4(position, 1.0));
+    output.coarseVertex.uv = input.assembledVertex.getUv();
+    output.coarseVertex.color = input.assembledVertex.getColorSet();
+    return output;
+}
+
+// Fragment Shader
+
+struct FragmentStageInput
+{
+    CoarseVertex coarseVertex : CoarseVertex;
+};
+
+struct FragmentStageOutput
+{
+    Fragment fragment : SV_Target;
+};
+
+FragmentStageOutput fragmentMain(FragmentStageInput input)
+{
+    FragmentStageOutput output;
+    float3 color = input.coarseVertex.color.getColor();
+    float2 uv = input.coarseVertex.uv;
+    output.fragment.color = float4(color, 1.0);
+    outputBuffer[0] = 1.0;
+    return output;
+}
diff --git a/tests/compute/type-param-varying.slang.expected.txt b/tests/compute/type-param-varying.slang.expected.txt
new file mode 100644
index 000000000..47b9ba0c8
--- /dev/null
+++ b/tests/compute/type-param-varying.slang.expected.txt
@@ -0,0 +1 @@
+3F800000
\ No newline at end of file
-- 
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