[vala/0.48] vala: Fix signals with generic return

[Rico Tzschichholz <ricotz src gnome org>]

commit 8df402c3bbed9fab6b15470b1a8c90e83888877a
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Fri Nov 26 15:34:40 2021 +0100

    vala: Fix signals with generic return
    
    In addition to 36999b5ffd63cc56a8648791b02bf07e7da88077

 codegen/valagsignalmodule.vala            |  4 ++--
 tests/Makefile.am                         |  1 +
 tests/objects/signals-generic-return.vala | 39 +++++++++++++++++++++++++++++++
 vala/valasignal.vala                      |  7 ++++--
 4 files changed, 47 insertions(+), 4 deletions(-)
---
diff --git a/codegen/valagsignalmodule.vala b/codegen/valagsignalmodule.vala
index 24ebfd252..f3cefdd56 100644
--- a/codegen/valagsignalmodule.vala
+++ b/codegen/valagsignalmodule.vala
@@ -242,7 +242,7 @@ public class Vala.GSignalModule : GObjectModule {
 
                CCodeFunctionCall fc;
 
-               if (return_type.type_symbol != null || return_type is ArrayType) {
+               if (return_type.type_symbol != null || return_type is ArrayType || return_type is 
GenericType) {
                        ccode.add_declaration (get_value_type_name_from_type_reference (return_type), new 
CCodeVariableDeclarator ("v_return"));
 
                        fc = new CCodeFunctionCall (new CCodeIdentifier ("g_return_if_fail"));
@@ -318,7 +318,7 @@ public class Vala.GSignalModule : GObjectModule {
                }
                fc.add_argument (new CCodeIdentifier ("data2"));
 
-               if (return_type.type_symbol != null || return_type is ArrayType) {
+               if (return_type.type_symbol != null || return_type is ArrayType || return_type is 
GenericType) {
                        ccode.add_assignment (new CCodeIdentifier ("v_return"), fc);
 
                        CCodeFunctionCall set_fc;
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 11e04ab85..5fd4c0883 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -525,6 +525,7 @@ TESTS = \
        objects/signals-dynamic-lambda-handler.test \
        objects/signals-error-marshal.vala \
        objects/signals-fundamental-return.vala \
+       objects/signals-generic-return.vala \
        objects/signals-gobject-return.vala \
        objects/signals-lambda-delegate.vala \
        objects/signals-prototype-access.vala \
diff --git a/tests/objects/signals-generic-return.vala b/tests/objects/signals-generic-return.vala
new file mode 100644
index 000000000..410cdc789
--- /dev/null
+++ b/tests/objects/signals-generic-return.vala
@@ -0,0 +1,39 @@
+class Foo<G,T> : Object {
+       public signal G on_foo ();
+       public signal T on_bar ();
+}
+
+int cb_foo () {
+       return 23;
+}
+
+string cb_bar () {
+       return "foo";
+}
+
+void main () {
+       {
+               var foo = new Foo<int,string> ();
+               foo.on_foo.connect (() => {
+                       return 42;
+               });
+               foo.on_bar.connect (() => {
+                       return "bar";
+               });
+
+               var bar = foo.on_foo ();
+               assert (bar == 42);
+               var bar2 = foo.on_bar ();
+               assert (bar2 == "bar");
+       }
+       {
+               var foo = new Foo<int,string> ();
+               foo.on_foo.connect (cb_foo);
+               foo.on_bar.connect (cb_bar);
+
+               var bar = foo.on_foo ();
+               assert (bar == 23);
+               var bar2 = foo.on_bar ();
+               assert (bar2 == "foo");
+       }
+}
diff --git a/vala/valasignal.vala b/vala/valasignal.vala
index 8a173b4c8..a96ab3793 100644
--- a/vala/valasignal.vala
+++ b/vala/valasignal.vala
@@ -115,7 +115,7 @@ public class Vala.Signal : Symbol, Callable {
 
                generated_delegate.sender_type = sender_param_type;
 
-               bool is_generic = false;
+               bool is_generic = actual_return_type.is_generic ();
 
                foreach (Parameter param in parameters) {
                        var actual_param = param.copy ();
@@ -133,8 +133,11 @@ public class Vala.Signal : Symbol, Callable {
                                generated_delegate.add_type_parameter (new TypeParameter (type_param.name, 
type_param.source_reference));
                        }
 
-                       // parameter types must refer to the delegate type parameters
+                       // return type and parameter types must refer to the delegate type parameters
                        // instead of to the class type parameters
+                       foreach (var type_param in generated_delegate.get_type_parameters ()) {
+                               actual_return_type.replace_type_parameter (cl.get_type_parameters ().get 
(cl.get_type_parameter_index (type_param.name)), type_param);
+                       }
                        foreach (var param in generated_delegate.get_parameters ()) {
                                foreach (var type_param in generated_delegate.get_type_parameters ()) {
                                        param.variable_type.replace_type_parameter (cl.get_type_parameters 
().get (cl.get_type_parameter_index (type_param.name)), type_param);