syntax: Update check_conform_multiexpr with nullables

[nit.git] / src / syntax / syntax_base.nit

diff --git a/src/syntax/syntax_base.nit b/src/syntax/syntax_base.nit
index e5b492d..ab1ced0 100644 (file)
--- a/src/syntax/syntax_base.nit
+++ b/src/syntax/syntax_base.nit
@@ -401,16 +401,23 @@ special Visitor
        # Conformance is granted if among them there is a most general type
        # Return the most general type if a conformance is found
        # Display an error and return null if no conformance is found
+       # The only allowed combinaison is with the nullable marker
        # @param stype is a possible additional type (without node)
        # Examples:
        #   Int, Int, Object => return Object
        #   Int, Float => display error, return null
+       #   nullable Int, Object => return nullable Object
        meth check_conform_multiexpr(stype: MMType, nodes: Collection[PExpr]): MMType
        do
                var node: PExpr = null # candidate node
                for n in nodes do
                        if not check_expr(n) then return null
                        var ntype = n.stype
+                       if stype != null and stype.is_nullable != ntype.is_nullable then
+                               # nullable combinaison: if one of them is nulable, considers that both are
+                               stype = stype.as_nullable
+                               ntype = ntype.as_nullable
+                       end
                        if stype == null or (ntype != null and stype < ntype) then
                                stype = ntype
                                node = n