Add clear diagnostic for unsupported float types in generic value parameters (#7737)

* Initial plan

* Add validation and clear error message for float generic parameters

Co-authored-by: csyonghe <2652293+csyonghe@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: csyonghe <2652293+csyonghe@users.noreply.github.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/tests/diagnostics/generic-value-parameter-float-type.slang b/tests/diagnostics/generic-value-parameter-float-type.slang
new file mode 100644
index 000000000..0f9cde255
--- /dev/null
+++ b/tests/diagnostics/generic-value-parameter-float-type.slang
@@ -0,0 +1,41 @@
+//DIAGNOSTIC_TEST:SIMPLE(filecheck=CHECK): -target spirv
+
+// Test that generic value parameters with float types are properly rejected
+
+// CHECK: error 30624: generic value parameter type 'float' is not supported
+struct ColorDefiner<let TMult : float>
+{
+    float4 color = {0.3, 0.7, 0.55, 1.0};
+
+    float4 get_color() { return color * TMult; }
+}
+
+// CHECK: error 30624: generic value parameter type 'double' is not supported
+struct DoubleDefiner<let TMult : double>
+{
+    float4 color = {0.3, 0.7, 0.55, 1.0};
+
+    float4 get_color() { return color * float(TMult); }
+}
+
+// Integer types should work fine (no error expected)
+struct IntDefiner<let TMult : int>
+{
+    float4 color = {0.3, 0.7, 0.55, 1.0};
+
+    float4 get_color() { return color * TMult; }
+}
+
+// Enum types should work fine (no error expected)
+enum Color { Red = 1, Green = 2, Blue = 3 }
+
+struct EnumDefiner<let TMult : Color>
+{
+    float4 color = {0.3, 0.7, 0.55, 1.0};
+
+    float4 get_color() { return color * int(TMult); }
+}
+
+void computeMain()
+{
+}
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