model: document the `assert isa MClassType`

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/model/model.nit b/src/model/model.nit
index 67b8161..d7d2cd2 100644 (file)
--- a/src/model/model.nit
+++ b/src/model/model.nit
@@ -1308,7 +1308,8 @@ class MParameterType
        redef fun lookup_bound(mmodule: MModule, resolved_receiver: MType): MType
        do
                assert not resolved_receiver.need_anchor
-               assert resolved_receiver isa MClassType
+               resolved_receiver = resolved_receiver.as_notnullable
+               assert resolved_receiver isa MClassType # It is the only remaining type
                var goalclass = self.mclass
                if resolved_receiver.mclass == goalclass then
                        return resolved_receiver.arguments[self.rank]
@@ -1334,7 +1335,9 @@ class MParameterType
        #   See `resolve_for` for examples about related issues.
        redef fun lookup_fixed(mmodule: MModule, resolved_receiver: MType): MType
        do
-               assert resolved_receiver isa MClassType
+               assert not resolved_receiver.need_anchor
+               resolved_receiver = resolved_receiver.as_notnullable
+               assert resolved_receiver isa MClassType # It is the only remaining type
                var res = self.resolve_for(resolved_receiver.mclass.mclass_type, resolved_receiver, mmodule, false)
                return res
        end
@@ -1371,7 +1374,7 @@ class MParameterType
                        resolved_receiver = anchor.arguments[resolved_receiver.rank]
                        if resolved_receiver isa MNullableType then resolved_receiver = resolved_receiver.mtype
                end
-               assert resolved_receiver isa MClassType
+               assert resolved_receiver isa MClassType # It is the only remaining type
 
                # Eh! The parameter is in the current class.
                # So we return the corresponding argument, no mater what!