[vala] Allow specialization of generic properties

[Luca Bruno <lucabru src gnome org>]

commit 556a22f808de35dbdfd510c287de1f5f3806f60a
Author: Luca Bruno <lucabru src gnome org>
Date:   Tue Jan 24 14:29:44 2012 +0100

    Allow specialization of generic properties
    
    Fixes bug 667668.

 tests/Makefile.am            |    1 +
 tests/objects/bug667668.vala |   13 +++++++++++
 vala/valaproperty.vala       |   48 ++++++++++++++++++++++++++---------------
 3 files changed, 44 insertions(+), 18 deletions(-)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 931db33..119f1f8 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -123,6 +123,7 @@ TESTS = \
 	objects/bug654702.vala \
 	objects/bug663134.vala \
 	objects/bug664529.vala \
+	objects/bug667668.vala \
 	errors/errors.vala \
 	errors/bug567181.vala \
 	errors/bug579101.vala \
diff --git a/tests/objects/bug667668.vala b/tests/objects/bug667668.vala
new file mode 100644
index 0000000..8f760c7
--- /dev/null
+++ b/tests/objects/bug667668.vala
@@ -0,0 +1,13 @@
+public abstract class Foo<G> : Object {
+	public abstract G foo { get; set; }
+}
+
+public class Bar : Foo<string> {
+	public override string foo { get; set; }
+}
+
+void main () {
+	var bar = new Bar ();
+	bar.foo = "foo";
+	assert (bar.foo == "foo");
+}
diff --git a/vala/valaproperty.vala b/vala/valaproperty.vala
index 7816020..1502758 100644
--- a/vala/valaproperty.vala
+++ b/vala/valaproperty.vala
@@ -189,28 +189,34 @@ public class Vala.Property : Symbol, Lockable {
 	}
 	
 	/**
-	 * Checks whether the accessors and type of the specified property
-	 * matches this property.
+	 * Checks whether the accessors of this property are compatible
+	 * with the specified base property.
 	 *
-	 * @param prop a property
-	 * @return     true if the specified property is compatible to this
-	 *             property
+	 * @param base_property a property
+	 * @param invalid_match error string about which check failed
+	 * @return true if the specified property is compatible to this property
 	 */
-	public bool equals (Property prop2) {
-		if ((get_accessor == null && prop2.get_accessor != null) ||
-		    (get_accessor != null && prop2.get_accessor == null)) {
+	public bool compatible (Property base_property, out string? invalid_match) {
+		if ((get_accessor == null && base_property.get_accessor != null) ||
+		    (get_accessor != null && base_property.get_accessor == null)) {
+			invalid_match = "incompatible get accessor";
 			return false;
 		}
 
-		if ((set_accessor == null && prop2.set_accessor != null) ||
-		    (set_accessor != null && prop2.set_accessor == null)) {
+		if ((set_accessor == null && base_property.set_accessor != null) ||
+		    (set_accessor != null && base_property.set_accessor == null)) {
+			invalid_match = "incompatible set accessor";
 			return false;
 		}
 
+		var object_type = CodeContext.get().analyzer.get_data_type_for_symbol ((TypeSymbol) parent_symbol);
+
 		if (get_accessor != null) {
 			// check accessor value_type instead of property_type
 			// due to possible ownership differences
-			if (!prop2.get_accessor.value_type.equals (get_accessor.value_type)) {
+			var actual_base_type = base_property.get_accessor.value_type.get_actual_type (object_type, null, this);
+			if (!actual_base_type.equals (get_accessor.value_type)) {
+				invalid_match = "incompatible get accessor type";
 				return false;
 			}
 		}
@@ -218,14 +224,18 @@ public class Vala.Property : Symbol, Lockable {
 		if (set_accessor != null) {
 			// check accessor value_type instead of property_type
 			// due to possible ownership differences
-			if (!prop2.set_accessor.value_type.equals (set_accessor.value_type)) {
+			var actual_base_type = base_property.set_accessor.value_type.get_actual_type (object_type, null, this);
+			if (!actual_base_type.equals (set_accessor.value_type)) {
+				invalid_match = "incompatible set accessor type";
 				return false;
 			}
 
-			if (set_accessor.writable != prop2.set_accessor.writable) {
+			if (set_accessor.writable != base_property.set_accessor.writable) {
+				invalid_match = "incompatible set accessor";
 				return false;
 			}
-			if (set_accessor.construction != prop2.set_accessor.construction) {
+			if (set_accessor.construction != base_property.set_accessor.construction) {
+				invalid_match = "incompatible set accessor";
 				return false;
 			}
 		}
@@ -263,9 +273,10 @@ public class Vala.Property : Symbol, Lockable {
 		if (sym is Property) {
 			var base_property = (Property) sym;
 			if (base_property.is_abstract || base_property.is_virtual) {
-				if (!equals (base_property)) {
+				string invalid_match;
+				if (!compatible (base_property, out invalid_match)) {
 					error = true;
-					Report.error (source_reference, "Type and/or accessors of overriding property `%s' do not match overridden property `%s'.".printf (get_full_name (), base_property.get_full_name ()));
+					Report.error (source_reference, "Type and/or accessors of overriding property `%s' do not match overridden property `%s': %s.".printf (get_full_name (), base_property.get_full_name (), invalid_match));
 					return;
 				}
 
@@ -287,9 +298,10 @@ public class Vala.Property : Symbol, Lockable {
 				if (sym is Property) {
 					var base_property = (Property) sym;
 					if (base_property.is_abstract) {
-						if (!equals (base_property)) {
+						string invalid_match;
+						if (!compatible (base_property, out invalid_match)) {
 							error = true;
-							Report.error (source_reference, "Type and/or accessors of overriding property `%s' do not match overridden property `%s'.".printf (get_full_name (), base_property.get_full_name ()));
+							Report.error (source_reference, "Type and/or accessors of overriding property `%s' do not match overridden property `%s': %s.".printf (get_full_name (), base_property.get_full_name (), invalid_match));
 							return;
 						}