Fix IR lowering for generic interface types. (#4761)

* Fix IR lowering for generic interface types.

* Fix.

* Fix.

1 files changed, 33 insertions, 0 deletions

diff --git a/tests/language-feature/constants/static-const-in-generic-interface.slang b/tests/language-feature/constants/static-const-in-generic-interface.slang
new file mode 100644
index 000000000..87d8e3be8
--- /dev/null
+++ b/tests/language-feature/constants/static-const-in-generic-interface.slang
@@ -0,0 +1,33 @@
+// static-const-in-generic-interface.slang
+
+//TEST(compute):COMPARE_COMPUTE(filecheck-buffer=CHECK): -shaderobj
+
+// Test that `static const` variable declarations inside of
+// a generic `interface` type correctly translate to interface requirements.
+
+interface ITest<T:__BuiltinIntegerType>
+{
+    static const T kUserDefinedValue;
+}
+
+struct Impl : ITest<int>
+{
+    static const int kUserDefinedValue = 4;
+}
+
+struct EnsureCompileTimeEval<T : __BuiltinIntegerType>
+{
+    static T getValue<U : ITest<T>>() { return U.kUserDefinedValue; }
+}
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<int> outputBuffer;
+
+[numthreads(1, 1, 1)]
+void computeMain(int3 dispatchThreadID : SV_DispatchThreadID)
+{
+    static const int result = EnsureCompileTimeEval<int>.getValue<Impl>();
+    int outVal = result;
+    // CHECK: 4
+    outputBuffer[0] = outVal;
+}