[vala/wip/baedert/nullable: 4/4] datatype: Properly mark generic types nullable

[Timm Bäder <baedert src gnome org>]

commit 8e49cbbb209bcb2cb0707824d7e87c1a8f1febb2
Author: Timm Bäder <mail baedert org>
Date:   Tue Nov 1 15:39:09 2016 +0100

    datatype: Properly mark generic types nullable
    
    Breaks everything.

 vala/valadatatype.vala |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/vala/valadatatype.vala b/vala/valadatatype.vala
index f3f9bf9..194ec9f 100644
--- a/vala/valadatatype.vala
+++ b/vala/valadatatype.vala
@@ -456,6 +456,13 @@ public abstract class Vala.DataType : CodeNode {
 
                if (result is GenericType) {
                        result = SemanticAnalyzer.get_actual_type (derived_instance_type, 
method_type_arguments, (GenericType) result, node_reference);
+                       // For Foo<G> and new Foo<Some>, this will resolve every occurrence of G to
+                       // 'Some', even though a) all generic types are nullable and
+                       // b) G might be used in a nullable context, i.e. G?.
+                       if (this.nullable && !(result is ValueType)) {
+                               result.nullable = true;
+                       }
+
                        // don't try to resolve type arguments of returned actual type
                        // they can never be resolved and are not related to the instance type
                } else if (result.type_argument_list != null) {