From: Lorenz Wildberg <lorenz@wild-fisch.de>
Date: Wed, 17 May 2023 19:27:56 +0000 (+0200)
Subject: generics-constraints: add test and improve error message
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fe6e331f006fadd371d82c42a6b111dd8e9d7819;p=thirdparty%2Fvala.git

generics-constraints: add test and improve error message
---

diff --git a/tests/generics/multiple-classes-constraints.test b/tests/generics/multiple-classes-constraints.test
new file mode 100644
index 000000000..4ca319f41
--- /dev/null
+++ b/tests/generics/multiple-classes-constraints.test
@@ -0,0 +1,9 @@
+Invalid Code
+
+class Foo {}
+class Fuu {}
+
+class Bar<G> where G : Foo, Fuu {
+}
+
+void main () {}
\ No newline at end of file
diff --git a/vala/valagenericsymbol.vala b/vala/valagenericsymbol.vala
index 54de02145..8037afaa5 100644
--- a/vala/valagenericsymbol.vala
+++ b/vala/valagenericsymbol.vala
@@ -53,4 +53,14 @@ public interface Vala.GenericSymbol : Symbol {
 	 * @return index of a type parameter, or -1
 	 */
 	public abstract int get_type_parameter_index (string name);
+
+	public bool check_constraints () {
+		bool error = false;
+		foreach (var parameter in this.get_type_parameters ()) {
+			if (!parameter.check_constraint ()) {
+				error = true;
+			}
+		}
+		return !error;
+	}
 }
diff --git a/vala/valaobjecttypesymbol.vala b/vala/valaobjecttypesymbol.vala
index 0ba8c6d70..94dd53cc3 100644
--- a/vala/valaobjecttypesymbol.vala
+++ b/vala/valaobjecttypesymbol.vala
@@ -381,6 +381,10 @@ public abstract class Vala.ObjectTypeSymbol : TypeSymbol, GenericSymbol {
 			return !error;
 		}
 
+		if (!this.check_constraints ()) {
+			error = true;
+		}
+
 		if (!external_package && has_attribute ("DBus") && !context.has_package ("gio-2.0")) {
 			error = true;
 			Report.error (source_reference, "gio-2.0 package required for DBus support");
diff --git a/vala/valatypeparameter.vala b/vala/valatypeparameter.vala
index e8c6bb61d..bcf383b10 100644
--- a/vala/valatypeparameter.vala
+++ b/vala/valatypeparameter.vala
@@ -141,6 +141,20 @@ public class Vala.TypeParameter : TypeSymbol {
 		return name == param2.name && parent_symbol == param2.parent_symbol;
 	}
 
+	public bool check_constraint () {
+		bool class_constraint = false;
+		foreach (var type in get_type_constraints ()) {
+			if (type.symbol is Class) {
+				if (class_constraint) {
+					Report.error (source_reference, "a type parameter can only be constrained with one class type");
+					return false;
+				}
+				class_constraint = true;
+			}
+		}
+		return true;
+	}
+
 	public override bool check (CodeContext context) {
 		if (checked) {
 			return !error;