vala: Don't make GenericType nullable by default

Allow equality between nullable and non-nullable generic-types for now

Fixes https://gitlab.gnome.org/GNOME/vala/issues/1191

13 files changed, 206 insertions, 17 deletions

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 99cee6206..daf2a8cf9 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -801,6 +801,7 @@ TESTS = \
 	generics/constructor-chain-up.vala \
 	generics/delegate-return-type-missing.test \
 	generics/floating-type-cast.vala \
+	generics/foreach-iterator-nullable.vala \
 	generics/gvariant-serialization.test \
 	generics/inference-argument-may-fail.vala \
 	generics/inference-static-function.vala \
@@ -1361,6 +1362,8 @@ TESTS = \
 	nullability/array-element-class.vala \
 	nullability/array-element-string.vala \
 	nullability/bug611223.vala \
+	nullability/generics-invalid.test \
+	nullability/generics.vala \
 	nullability/local-variable-invalid-convert.test \
 	nullability/member-access-narrowed-instance.vala \
 	nullability/member-access-nullable-instance.test \
diff --git a/tests/generics/foreach-iterator-nullable.c-expected b/tests/generics/foreach-iterator-nullable.c-expected
new file mode 100644
index 000000000..ba88ee255
--- /dev/null
+++ b/tests/generics/foreach-iterator-nullable.c-expected
@@ -0,0 +1,98 @@
+/* generics_foreach_iterator_nullable.c generated by valac, the Vala compiler
+ * generated from generics_foreach_iterator_nullable.vala, do not modify */
+
+#include <glib.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define _g_hash_table_unref0(var) ((var == NULL) ? NULL : (var = (g_hash_table_unref (var), NULL)))
+#define _vala_assert(expr, msg) if G_LIKELY (expr) ; else g_assertion_message_expr (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, msg);
+#define _vala_return_if_fail(expr, msg) if G_LIKELY (expr) ; else { g_return_if_fail_warning (G_LOG_DOMAIN, G_STRFUNC, msg); return; }
+#define _vala_return_val_if_fail(expr, msg, val) if G_LIKELY (expr) ; else { g_return_if_fail_warning (G_LOG_DOMAIN, G_STRFUNC, msg); return val; }
+#define _vala_warn_if_fail(expr, msg) if G_LIKELY (expr) ; else g_warn_message (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, msg);
+
+static void _vala_main (void);
+static void _g_free0_ (gpointer var);
+
+static void
+_g_free0_ (gpointer var)
+{
+	var = (g_free (var), NULL);
+}
+
+static gconstpointer
+_vala_hash_set_next_value (GHashTableIter *self)
+{
+	void* vi = NULL;
+	GHashTableIter* htp = NULL;
+	void* _tmp0_;
+	gconstpointer value = NULL;
+	gconstpointer _tmp1_ = NULL;
+	gconstpointer _tmp2_ = NULL;
+	gboolean _tmp3_;
+	gconstpointer result;
+	vi = &(*self);
+	_tmp0_ = vi;
+	htp = _tmp0_;
+	_tmp3_ = g_hash_table_iter_next (htp, (gpointer*) (&_tmp2_), (gpointer*) NULL);
+	value = _tmp2_;
+	if (_tmp3_) {
+		gconstpointer _tmp4_;
+		_tmp4_ = value;
+		_tmp1_ = _tmp4_;
+	} else {
+		_tmp1_ = NULL;
+	}
+	result = _tmp1_;
+	return result;
+}
+
+static void
+_vala_main (void)
+{
+	GHashTable* gs = NULL;
+	GHashFunc _tmp0_;
+	GEqualFunc _tmp1_;
+	GHashTable* _tmp2_;
+	GHashTable* _tmp3_;
+	gchar* _tmp4_;
+	_tmp0_ = g_str_hash;
+	_tmp1_ = g_str_equal;
+	_tmp2_ = g_hash_table_new_full (_tmp0_, _tmp1_, NULL, _g_free0_);
+	gs = _tmp2_;
+	_tmp3_ = gs;
+	_tmp4_ = g_strdup ("foo");
+	g_hash_table_add (_tmp3_, _tmp4_);
+	{
+		GHashTableIter _s_it = {0};
+		GHashTable* _tmp5_;
+		GHashTableIter _tmp6_ = {0};
+		const gchar* s = NULL;
+		_tmp5_ = gs;
+		g_hash_table_iter_init (&_tmp6_, _tmp5_);
+		_s_it = _tmp6_;
+		while (TRUE) {
+			gconstpointer _tmp7_;
+			const gchar* _tmp8_;
+			const gchar* _tmp9_;
+			_tmp7_ = _vala_hash_set_next_value (&_s_it);
+			s = (const gchar*) _tmp7_;
+			_tmp8_ = s;
+			if (!(_tmp8_ != NULL)) {
+				break;
+			}
+			_tmp9_ = s;
+			_vala_assert (g_strcmp0 (_tmp9_, "foo") == 0, "s == \"foo\"");
+		}
+	}
+	_g_hash_table_unref0 (gs);
+}
+
+int
+main (int argc,
+      char ** argv)
+{
+	_vala_main ();
+	return 0;
+}
+
diff --git a/tests/generics/foreach-iterator-nullable.vala b/tests/generics/foreach-iterator-nullable.vala
new file mode 100644
index 000000000..3c23d3df6
--- /dev/null
+++ b/tests/generics/foreach-iterator-nullable.vala
@@ -0,0 +1,7 @@
+void main () {
+	var gs = new GenericSet<string> (GLib.str_hash, GLib.str_equal);
+	gs.add ("foo");
+	foreach (var s in gs) {
+		assert (s == "foo");
+	}
+}
diff --git a/tests/girwriter/GirTest-1.0.gir-expected b/tests/girwriter/GirTest-1.0.gir-expected
index c308e62a1..5aafe5126 100644
--- a/tests/girwriter/GirTest-1.0.gir-expected
+++ b/tests/girwriter/GirTest-1.0.gir-expected
@@ -2935,7 +2935,7 @@
 			<parameter name="t_destroy_func" transfer-ownership="none">
 				<type name="GLib.DestroyNotify" c:type="GDestroyNotify"/>
 			</parameter>
-			<parameter name="g" transfer-ownership="none" nullable="1">
+			<parameter name="g" transfer-ownership="none">
 				<type name="gpointer" c:type="gpointer"/>
 			</parameter>
 			<parameter name="t" transfer-ownership="none" nullable="1">
diff --git a/tests/girwriter/girtest.vala b/tests/girwriter/girtest.vala
index b2b107385..1125bfa1c 100644
--- a/tests/girwriter/girtest.vala
+++ b/tests/girwriter/girtest.vala
@@ -163,7 +163,7 @@ namespace GirTest {
 
 	public delegate bool DelegateErrorTest () throws ErrorTest;
 
-	public delegate bool DelegateGenericsTest<G,T> (G g, T t);
+	public delegate bool DelegateGenericsTest<G,T> (G g, T? t);
 
 	[GIR (visible = false)]
 	public delegate void SkippedDelegate ();
@@ -436,7 +436,7 @@ namespace GirTest {
 		public GenericsTest.typed (owned DelegateGenericsTest<G,T> cb) {
 		}
 
-		public void method (T param) {
+		public void method (T? param) {
 		}
 	}
 
diff --git a/tests/girwriter/girtest.vapi-expected b/tests/girwriter/girtest.vapi-expected
index 578d588dc..b63aad4aa 100644
--- a/tests/girwriter/girtest.vapi-expected
+++ b/tests/girwriter/girtest.vapi-expected
@@ -40,7 +40,7 @@ namespace GirTest {
 	[CCode (cheader_filename = "girtest.h")]
 	public class GenericsTest<G,T> {
 		public GenericsTest (owned GirTest.DelegateTest cb);
-		public void method (T param);
+		public void method (T? param);
 		public GenericsTest.typed (owned GirTest.DelegateGenericsTest<G,T> cb);
 	}
 	[CCode (cheader_filename = "girtest.h")]
@@ -258,7 +258,7 @@ namespace GirTest {
 	[CCode (cheader_filename = "girtest.h")]
 	public delegate bool DelegateErrorTest () throws GirTest.ErrorTest;
 	[CCode (cheader_filename = "girtest.h")]
-	public delegate bool DelegateGenericsTest<G,T> (G g, T t);
+	public delegate bool DelegateGenericsTest<G,T> (G g, T? t);
 	[CCode (cheader_filename = "girtest.h")]
 	public delegate bool DelegateTest (void* a, void* b);
 	[CCode (cheader_filename = "girtest.h")]
diff --git a/tests/nullability/generics-invalid.test b/tests/nullability/generics-invalid.test
new file mode 100644
index 000000000..e82fd74d5
--- /dev/null
+++ b/tests/nullability/generics-invalid.test
@@ -0,0 +1,16 @@
+Invalid Code
+
+G? foo<G> () {
+	return null;
+}
+
+void manam<K> (K k) {
+}
+
+void bar<T> () {
+	T t = foo<T> ();
+	manam (t);
+}
+
+void main () {
+}
diff --git a/tests/nullability/generics.c-expected b/tests/nullability/generics.c-expected
new file mode 100644
index 000000000..ca4783adb
--- /dev/null
+++ b/tests/nullability/generics.c-expected
@@ -0,0 +1,58 @@
+/* nullability_generics.c generated by valac, the Vala compiler
+ * generated from nullability_generics.vala, do not modify */
+
+#include <glib-object.h>
+#include <glib.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if !defined(VALA_EXTERN)
+#if defined(_WIN32) || defined(__CYGWIN__)
+#define VALA_EXTERN __declspec(dllexport) extern
+#elif __GNUC__ >= 4
+#define VALA_EXTERN __attribute__((visibility("default"))) extern
+#else
+#define VALA_EXTERN extern
+#endif
+#endif
+
+#define _g_free0(var) (var = (g_free (var), NULL))
+#define _vala_assert(expr, msg) if G_LIKELY (expr) ; else g_assertion_message_expr (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, msg);
+#define _vala_return_if_fail(expr, msg) if G_LIKELY (expr) ; else { g_return_if_fail_warning (G_LOG_DOMAIN, G_STRFUNC, msg); return; }
+#define _vala_return_val_if_fail(expr, msg, val) if G_LIKELY (expr) ; else { g_return_if_fail_warning (G_LOG_DOMAIN, G_STRFUNC, msg); return val; }
+#define _vala_warn_if_fail(expr, msg) if G_LIKELY (expr) ; else g_warn_message (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, msg);
+
+VALA_EXTERN gpointer foo (GType g_type,
+              GBoxedCopyFunc g_dup_func,
+              GDestroyNotify g_destroy_func);
+static void _vala_main (void);
+
+gpointer
+foo (GType g_type,
+     GBoxedCopyFunc g_dup_func,
+     GDestroyNotify g_destroy_func)
+{
+	gpointer result;
+	result = NULL;
+	return result;
+}
+
+static void
+_vala_main (void)
+{
+	gchar* s = NULL;
+	gpointer _tmp0_;
+	_tmp0_ = foo (G_TYPE_STRING, (GBoxedCopyFunc) g_strdup, (GDestroyNotify) g_free);
+	s = (gchar*) _tmp0_;
+	_vala_assert (s == NULL, "s == null");
+	_g_free0 (s);
+}
+
+int
+main (int argc,
+      char ** argv)
+{
+	_vala_main ();
+	return 0;
+}
+
diff --git a/tests/nullability/generics.vala b/tests/nullability/generics.vala
new file mode 100644
index 000000000..8568f8baa
--- /dev/null
+++ b/tests/nullability/generics.vala
@@ -0,0 +1,8 @@
+G? foo<G> () {
+	return null;
+}
+
+void main () {
+	var s = foo<string> ();
+	assert (s == null);
+}
diff --git a/vala/valadatatype.vala b/vala/valadatatype.vala
index fec7e9010..897eaf72c 100644
--- a/vala/valadatatype.vala
+++ b/vala/valadatatype.vala
@@ -204,7 +204,11 @@ public abstract class Vala.DataType : CodeNode {
 			return false;
 		}
 		if (type2.nullable != nullable) {
-			return false;
+			//TODO Allow equality between nullable and non-nullable generic-types
+			// This mitigation allows fixing affected source code without breaking it.
+			// It has to be removed at some point
+			var context = CodeContext.get ();
+			return !context.experimental_non_null && this is GenericType == type2 is GenericType;
 		}
 		if (type2.type_symbol != type_symbol) {
 			return false;
diff --git a/vala/valagenerictype.vala b/vala/valagenerictype.vala
index 32b32ba0e..50c713bce 100644
--- a/vala/valagenerictype.vala
+++ b/vala/valagenerictype.vala
@@ -40,8 +40,6 @@ public class Vala.GenericType : DataType {
 
 	public GenericType (TypeParameter type_parameter, SourceReference? source_reference = null) {
 		base.with_symbol (type_parameter, source_reference);
-		// type parameters are always considered nullable
-		this.nullable = true;
 	}
 
 	public override DataType copy () {
@@ -62,6 +60,9 @@ public class Vala.GenericType : DataType {
 		}
 
 		result = SemanticAnalyzer.get_actual_type (derived_instance_type, method_type_arguments, (GenericType) result, node_reference);
+		if (!result.is_non_null_simple_type ()) {
+			result.nullable = result.nullable || nullable;
+		}
 
 		return result;
 	}
@@ -77,7 +78,7 @@ public class Vala.GenericType : DataType {
 	}
 
 	public override string to_qualified_string (Scope? scope = null) {
-		return type_parameter.name;
+		return "%s%s".printf (type_parameter.name, nullable ? "?" : "");
 	}
 
 	public override Symbol? get_member (string member_name) {
diff --git a/vala/valamemberaccess.vala b/vala/valamemberaccess.vala
index 2b75adcc5..23078f25b 100644
--- a/vala/valamemberaccess.vala
+++ b/vala/valamemberaccess.vala
@@ -620,6 +620,7 @@ public class Vala.MemberAccess : Expression {
 		} else if (symbol_reference.error) {
 			//ignore previous error
 			error = true;
+			value_type = new InvalidType ();
 			return false;
 		}
 
diff --git a/vala/valasymbolresolver.vala b/vala/valasymbolresolver.vala
index 87352bd00..d029aa9a7 100644
--- a/vala/valasymbolresolver.vala
+++ b/vala/valasymbolresolver.vala
@@ -473,16 +473,9 @@ public class Vala.SymbolResolver : CodeVisitor {
 
 		type.source_reference = unresolved_type.source_reference;
 		type.value_owned = unresolved_type.value_owned;
+		type.nullable = unresolved_type.nullable;
 		sym.used = true;
 
-		if (type is GenericType) {
-			// type parameters are always considered nullable
-			// actual type argument may or may not be nullable
-			type.nullable = true;
-		} else {
-			type.nullable = unresolved_type.nullable;
-		}
-
 		type.is_dynamic = unresolved_type.is_dynamic;
 		foreach (DataType type_arg in unresolved_type.get_type_arguments ()) {
 			type.add_type_argument (type_arg);