From: Rico Tzschichholz <ricotz@ubuntu.com>
Date: Mon, 22 Jul 2019 10:49:53 +0000 (+0200)
Subject: codegen: Use G_TYPE_CHECK_INSTANCE_CAST for comparisons with interfaces
X-Git-Tag: 0.45.90~10
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5744eed9e8adcf7714bab17042188a508c510922;p=thirdparty%2Fvala.git

codegen: Use G_TYPE_CHECK_INSTANCE_CAST for comparisons with interfaces

Avoids "comparison of distinct pointer types lacks a cast" warning for
such cases.
---

diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index bef379bf1..783aa06e8 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -2808,19 +2808,18 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
 	}
 
 	void make_comparable_cexpression (ref DataType left_type, ref CCodeExpression cleft, ref DataType right_type, ref CCodeExpression cright) {
-		var left_type_as_struct = left_type.data_type as Struct;
-		var right_type_as_struct = right_type.data_type as Struct;
-
-		if (left_type.data_type is Class && !((Class) left_type.data_type).is_compact &&
-		    right_type.data_type is Class && !((Class) right_type.data_type).is_compact) {
-			var left_cl = (Class) left_type.data_type;
-			var right_cl = (Class) right_type.data_type;
-
-			if (left_cl != right_cl) {
-				if (left_cl.is_subtype_of (right_cl)) {
-					cleft = generate_instance_cast (cleft, right_cl);
-				} else if (right_cl.is_subtype_of (left_cl)) {
-					cright = generate_instance_cast (cright, left_cl);
+		unowned Struct? left_type_as_struct = left_type.data_type as Struct;
+		unowned Struct? right_type_as_struct = right_type.data_type as Struct;
+		unowned ObjectTypeSymbol? left_type_as_object_type = left_type.data_type as ObjectTypeSymbol;
+		unowned ObjectTypeSymbol? right_type_as_object_type = right_type.data_type as ObjectTypeSymbol;
+
+		if (left_type_as_object_type != null && (!(left_type_as_object_type is Class) || !((Class) left_type_as_object_type).is_compact)
+		    && right_type_as_object_type != null && (!(right_type_as_object_type is Class) || !((Class) right_type_as_object_type).is_compact)) {
+			if (left_type_as_object_type != right_type_as_object_type) {
+				if (left_type_as_object_type.is_subtype_of (right_type_as_object_type)) {
+					cleft = generate_instance_cast (cleft, right_type_as_object_type);
+				} else if (right_type_as_object_type.is_subtype_of (left_type_as_object_type)) {
+					cright = generate_instance_cast (cright, left_type_as_object_type);
 				}
 			}
 		} else if (left_type_as_struct != null && right_type_as_struct != null) {
diff --git a/configure.ac b/configure.ac
index aa8097b23..4dc975450 100644
--- a/configure.ac
+++ b/configure.ac
@@ -123,6 +123,7 @@ TEST_EXTRA_CFLAGS="-Werror=init-self \
 -Werror=uninitialized \
 -Werror=int-to-pointer-cast \
 -Werror=pointer-to-int-cast \
+-Werror=compare-distinct-pointer-types \
 -Wformat=2 \
 -Werror=format-security \
 -Werror=format-nonliteral \
diff --git a/tests/Makefile.am b/tests/Makefile.am
index dfa15aa95..da383549b 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -308,6 +308,7 @@ TESTS = \
 	objects/field-leading-digit.test \
 	objects/fields.vala \
 	objects/gsource.vala \
+	objects/instance-comparison.vala \
 	objects/interface_only.vala \
 	objects/interfaces.vala \
 	objects/interface-generics.vala \
diff --git a/tests/objects/instance-comparison.vala b/tests/objects/instance-comparison.vala
new file mode 100644
index 000000000..51f02c00c
--- /dev/null
+++ b/tests/objects/instance-comparison.vala
@@ -0,0 +1,54 @@
+interface IFoo : Object {
+}
+
+class Bar : Object, IFoo {
+}
+
+class Manam : Bar {
+}
+
+interface IFaz : Object, IFoo {
+}
+
+class Baz : Object, IFoo, IFaz {
+}
+
+void main () {
+	{
+		Bar bar = new Bar ();
+		IFoo foo = bar;
+
+		if (foo != bar) {
+			assert_not_reached ();
+		} else if (foo == bar) {
+			// Well done
+		} else {
+			assert_not_reached ();
+		}
+	}
+	{
+		IFaz faz = new Baz ();
+		IFoo foo = faz;
+
+		if (faz != foo) {
+			assert_not_reached ();
+		} else if (foo == faz) {
+			// Well done
+		} else {
+			assert_not_reached ();
+		}
+	}
+	{
+		Manam manam = new Manam ();
+		Bar bar = manam;
+
+		if (manam != bar) {
+			assert_not_reached ();
+		} else if (manam == bar) {
+			// Well done
+		} else {
+			assert_not_reached ();
+		}
+	}
+}
+