Metadata processing improvements (#2598)

Author: kennykerr

crates/libs/metadata/src/attributes.rs

@@ -61,11 +61,12 @@ impl MethodAttributes {
     pub const Virtual: Self = Self(0x40);
 }
 
-flags!(MethodImplAttributes, usize);
+flags!(MethodImplAttributes, u16);
 impl MethodImplAttributes {
     pub const PreserveSig: Self = Self(0x80);
 }
 
+// These are not really ECMA-335 attributes but instead the flags found in the method signature.
 flags!(MethodCallAttributes, u8);
 impl MethodCallAttributes {
     pub const HASTHIS: Self = Self(0x20);

crates/libs/metadata/src/file/reader.rs

@@ -175,6 +175,10 @@ pub trait RowReader<'a> {
     // GenericParam
     //
 
+    fn generic_param_number(&self, row: GenericParam) -> u16 {
+        self.row_usize(row, 0) as u16
+    }
+
     fn generic_param_name(&self, row: GenericParam) -> &'a str {
         self.row_str(row, 3)
     }
@@ -212,7 +216,7 @@ pub trait RowReader<'a> {
     //
 
     fn method_def_impl_flags(&self, row: MethodDef) -> MethodImplAttributes {
-        MethodImplAttributes(self.row_usize(row, 1))
+        MethodImplAttributes(self.row_usize(row, 1) as u16)
     }
 
     fn method_def_flags(&self, row: MethodDef) -> MethodAttributes {
@@ -268,8 +272,8 @@ pub trait RowReader<'a> {
         ParamAttributes(self.row_usize(row, 0) as u16)
     }
 
-    fn param_sequence(&self, row: Param) -> usize {
-        self.row_usize(row, 1)
+    fn param_sequence(&self, row: Param) -> u16 {
+        self.row_usize(row, 1) as u16
     }
 
     fn param_name(&self, row: Param) -> &'a str {
@@ -307,8 +311,8 @@ pub trait RowReader<'a> {
         self.row_list(row, 4)
     }
 
-    fn type_def_generics(&self, row: TypeDef) -> Vec<Type> {
-        self.row_equal_range(row, 2, TypeOrMethodDef::TypeDef(row).encode()).map(Type::GenericParam).collect()
+    fn type_def_generics(&self, row: TypeDef) -> RowIterator<GenericParam> {
+        self.row_equal_range(row, 2, TypeOrMethodDef::TypeDef(row).encode())
     }
 
     fn type_def_interface_impls(&self, row: TypeDef) -> RowIterator<InterfaceImpl> {