2006-01-18 Martin Baulig <martin@ximian.com>

	Fix #76417: a generic class may now have methods which may unify
	for some type parameter substitutions.

	* class.cs (Method.IsDuplicateImplementation): Don't report CS0408
	for methods which may unify anymore.

	* expression.cs (Invocation.MoreSpecific): New private static
	method; checks whether one method is more specific than another
	according to 14.4.2.2 of the spec.
	(Invocation.BetterFunction): Implement the tie-breaking rules from
	14.4.2.2 of the spec: if two methods unify for some type parameter
	substitution, we need to pick the more specific one.


svn path=/trunk/mcs/; revision=55728

1 files changed, 60 insertions, 0 deletions

diff --git a/mcs/tests/gtest-239.cs b/mcs/tests/gtest-239.cs
new file mode 100644
index 00000000000..6add5879654
--- /dev/null
+++ b/mcs/tests/gtest-239.cs
@@ -0,0 +1,60 @@
+using System;
+
+class Foo<T,U>
+{
+	public int Test (T t, U u)
+	{
+		return 1;
+	}
+
+	public int Test (int t, U u)
+	{
+		return 2;
+	}
+
+	public int Test (T t, float u)
+	{
+		return 3;
+	}
+
+	public int Test (int t, float u)
+	{
+		return 4;
+	}
+}
+
+class X
+{
+	static int Main ()
+	{
+		Foo<long,float> a = new Foo<long,float> ();
+		if (a.Test (3L, 3.14F) != 3)
+			return 1;
+		if (a.Test (3L, 8) != 3)
+			return 2;
+		if (a.Test (3, 3.14F) != 4)
+			return 3;
+		if (a.Test (3, 8) != 4)
+			return 4;
+
+		Foo<long,double> b = new Foo<long,double> ();
+		if (b.Test (3L, 3.14F) != 3)
+			return 5;
+		if (b.Test (3, 3.14F) != 4)
+			return 6;
+		if (b.Test (3L, 3.14F) != 3)
+			return 7;
+		if (b.Test (3L, 5) != 3)
+			return 8;
+
+		Foo<string,float> c = new Foo<string,float> ();
+		if (c.Test ("Hello", 3.14F) != 3)
+			return 9;
+
+		Foo<int,string> d = new Foo<int,string> ();
+		if (d.Test (3, "Hello") != 2)
+			return 10;
+
+		return 0;
+	}
+}