From: Rico Tzschichholz <ricotz@ubuntu.com>
Date: Thu, 13 Apr 2023 15:19:04 +0000 (+0200)
Subject: WIP vala: Check compatibility of generic type-arguments and type-constraints
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cb5abe89419fc435a6f8b9c0178f6f3a917cfc7b;p=thirdparty%2Fvala.git

WIP vala: Check compatibility of generic type-arguments and type-constraints
---

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 11a5469f4..a01040eae 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -808,6 +808,7 @@ TESTS = \
 	generics/arrays-not-supported-3.test \
 	generics/class-property-override.vala \
 	generics/constraints.vala \
+	generics/constraints-incompatible.test \
 	generics/constructor-chain-up.vala \
 	generics/delegate-return-type-missing.test \
 	generics/floating-type-cast.vala \
diff --git a/tests/generics/constraints-incompatible.test b/tests/generics/constraints-incompatible.test
new file mode 100644
index 000000000..1a9fec533
--- /dev/null
+++ b/tests/generics/constraints-incompatible.test
@@ -0,0 +1,16 @@
+Invalid Code
+
+class Bar {
+}
+
+class SubBar : Bar {
+}
+
+interface IFoo<G> where G : SubBar {
+}
+
+class Foo<T> : IFoo<T> where T : Bar {
+}
+
+void main () {
+}
diff --git a/vala/valadatatype.vala b/vala/valadatatype.vala
index a570f9d48..f947f7cdf 100644
--- a/vala/valadatatype.vala
+++ b/vala/valadatatype.vala
@@ -319,6 +319,10 @@ public abstract class Vala.DataType : CodeNode {
 
 		/* temporarily ignore type parameters */
 		if (target_type is GenericType) {
+			unowned DataType? constraint_type = ((GenericType) target_type).type_parameter.type_constraint;
+			if (constraint_type != null) {
+				return compatible (constraint_type);
+			}
 			return true;
 		}
 
@@ -721,10 +725,19 @@ public abstract class Vala.DataType : CodeNode {
 			return false;
 		}
 
+		var it = ((GenericSymbol) type_symbol).get_type_parameters ().iterator ();
 		foreach (DataType type in get_type_arguments ()) {
 			if (!type.check (context)) {
 				return false;
 			}
+
+			it.next ();
+			unowned DataType? constraint_type = it.get ().type_constraint;
+			if (constraint_type != null && !type.compatible (constraint_type)) {
+				error = true;
+				Report.error (type.source_reference, "Cannot convert from `%s' to `%s'", type.to_string (), constraint_type.to_string ());
+				return false;
+			}
 		}
 
 		return true;
diff --git a/vala/valagenerictype.vala b/vala/valagenerictype.vala
index 50c713bce..3a81449c1 100644
--- a/vala/valagenerictype.vala
+++ b/vala/valagenerictype.vala
@@ -52,6 +52,15 @@ public class Vala.GenericType : DataType {
 		return result;
 	}
 
+	public override bool compatible (DataType target_type) {
+		unowned DataType? constraint_type = type_parameter.type_constraint;
+		if (constraint_type != null) {
+			return constraint_type.compatible (target_type);
+		}
+
+		return base.compatible (target_type);
+	}
+
 	public override DataType get_actual_type (DataType? derived_instance_type, List<DataType>? method_type_arguments, CodeNode? node_reference) {
 		var result = this.copy ();