Index: src/AST/Attribute.cpp
===================================================================
--- src/AST/Attribute.cpp	(revision c7ebbec0b2465582b53d918f1a2b2c24f69f7ef1)
+++ src/AST/Attribute.cpp	(revision b262cb319ecbb4a4d3556a10cd2adc1ef8640982)
@@ -38,9 +38,10 @@
 
 bool Attribute::isValidOnFuncParam() const {
-	// attributes such as aligned, cleanup, etc. produce GCC errors when they appear
-	// on function parameters. Maintain here a whitelist of attribute names that are
-	// allowed to appear on parameters.
+	// Attributes produce GCC errors when they appear on function
+	// parameters. This is an allow-list, switching to a forbid-list would
+	// have to at least mention:
+	// aligned
 	std::string norm = normalizedName();
-	return norm == "unused" || norm == "noreturn";
+	return norm == "unused" || norm == "noreturn" || norm == "vector_size";
 }