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, 12 insertions, 0 deletions

diff --git a/source/slang/slang-check-decl.cpp b/source/slang/slang-check-decl.cpp
index 584b1f081..9853b0097 100644
--- a/source/slang/slang-check-decl.cpp
+++ b/source/slang/slang-check-decl.cpp
@@ -3413,6 +3413,18 @@ void SemanticsDeclHeaderVisitor::visitGenericTypeParamDecl(GenericTypeParamDecl*
 void SemanticsDeclHeaderVisitor::visitGenericValueParamDecl(GenericValueParamDecl* decl)
 {
     checkVarDeclCommon(decl);
+
+    // Validate that the type is supported for generic value parameters
+    if (decl->type.type)
+    {
+        if (!isValidCompileTimeConstantType(decl->type.type))
+        {
+            getSink()->diagnose(
+                decl,
+                Diagnostics::genericValueParameterTypeNotSupported,
+                decl->type.type);
+        }
+    }
 }
 
 void SemanticsDeclHeaderVisitor::visitGenericDecl(GenericDecl* genericDecl)