Reject empty struct types. (#1826)

src/lib.rs

@@ -676,6 +676,8 @@ pub enum TypeInner {
 
     /// User-defined structure.
     ///
+    /// There must always be at least one member.
+    ///
     /// A `Struct` type is [`DATA`], and the types of its members must be
     /// `DATA` as well.
     ///

src/valid/type.rs

@@ -120,6 +120,8 @@ pub enum TypeError {
         size: u32,
         span: u32,
     },
+    #[error("Structure types must have at least one member")]
+    EmptyStruct,
 }
 
 // Only makes sense if `flags.contains(HOST_SHARED)`
@@ -451,6 +453,10 @@ impl super::Validator {
                 }
             }
             Ti::Struct { ref members, span } => {
+                if members.is_empty() {
+                    return Err(TypeError::EmptyStruct);
+                }
+
                 let mut ti = TypeInfo::new(
                     TypeFlags::DATA
                         | TypeFlags::SIZED

tests/wgsl-errors.rs

@@ -930,6 +930,14 @@ fn invalid_structs() {
             ..
         })
     }
+
+    check_validation_error! {
+        "struct Empty {}":
+        Err(naga::valid::ValidationError::Type {
+            error: naga::valid::TypeError::EmptyStruct,
+            ..
+        })
+    }
 }
 
 #[test]