--- plugins/language-support-vala/plugin.vala.orig	2021-12-27 15:15:31.000000000 -0800
+++ plugins/language-support-vala/plugin.vala	2021-12-27 15:16:07.000000000 -0800
@@ -78,7 +78,11 @@
 
 	void init_context () {
 		context = new Vala.CodeContext();
+#if VALA_0_50
+		context.set_target_profile (Vala.Profile.GOBJECT);
+#else
 		context.profile = Vala.Profile.GOBJECT;
+#endif
 		context.report = report;
 		report.clear_error_indicators ();
 
@@ -414,11 +418,19 @@
 			builder.append_printf ("%s sender", widget.get_full_name ());
 
 			foreach (var param in sig.get_parameters ()) {
+#if VALA_0_48
+				builder.append_printf (", %s %s", param.variable_type.type_symbol.get_full_name (), param.name);
+#else
 				builder.append_printf (", %s %s", param.variable_type.data_type.get_full_name (), param.name);
+#endif
 			}
 		} else {
 			foreach (var param in sig.get_parameters ()) {
+#if VALA_0_48
+				builder.append_printf ("%s %s, ", param.variable_type.type_symbol.get_full_name (), param.name);
+#else
 				builder.append_printf ("%s %s, ", param.variable_type.data_type.get_full_name (), param.name);
+#endif
 			}
 
 			builder.append_printf ("%s sender", widget.get_full_name ());
@@ -563,6 +575,15 @@
 		}
 		return matching_symbols;
 	}
+
+	inline List<Vala.Symbol> symbol_lookup_inherited_for_type (Vala.DataType data_type, string name, bool prefix_match, bool invocation = false) {
+#if VALA_0_48
+		return symbol_lookup_inherited (data_type.type_symbol, name, prefix_match, invocation);
+#else
+		return symbol_lookup_inherited (data_type.data_type, name, prefix_match, invocation);
+#endif
+	}
+
 	List<Vala.Symbol> symbol_lookup_inherited (Vala.Symbol? sym, string name, bool prefix_match, bool invocation = false) {
 		List<Vala.Symbol> result = null;
 
@@ -580,32 +601,32 @@
 		}
 		if (invocation && sym is Vala.Method) {
 			var func = (Vala.Method) sym;
-			result.concat (symbol_lookup_inherited (func.return_type.data_type, name, prefix_match));
+			result.concat (symbol_lookup_inherited_for_type (func.return_type, name, prefix_match));
 		} else if (sym is Vala.Class) {
 			var cl = (Vala.Class) sym;
 			foreach (var base_type in cl.get_base_types ()) {
-				result.concat (symbol_lookup_inherited (base_type.data_type, name, prefix_match));
+				result.concat (symbol_lookup_inherited_for_type (base_type, name, prefix_match));
 			}
 		} else if (sym is Vala.Struct) {
 			var st = (Vala.Struct) sym;
-			result.concat (symbol_lookup_inherited (st.base_type.data_type, name, prefix_match));
+			result.concat (symbol_lookup_inherited_for_type (st.base_type, name, prefix_match));
 		} else if (sym is Vala.Interface) {
 			var iface = (Vala.Interface) sym;
 			foreach (var prerequisite in iface.get_prerequisites ()) {
-				result.concat (symbol_lookup_inherited (prerequisite.data_type, name, prefix_match));
+				result.concat (symbol_lookup_inherited_for_type (prerequisite, name, prefix_match));
 			}
 		} else if (sym is Vala.LocalVariable) {
 			var variable = (Vala.LocalVariable) sym;
-			result.concat (symbol_lookup_inherited (variable.variable_type.data_type, name, prefix_match));
+			result.concat (symbol_lookup_inherited_for_type (variable.variable_type, name, prefix_match));
 		} else if (sym is Vala.Field) {
 			var field = (Vala.Field) sym;
-			result.concat (symbol_lookup_inherited (field.variable_type.data_type, name, prefix_match));
+			result.concat (symbol_lookup_inherited_for_type (field.variable_type, name, prefix_match));
 		} else if (sym is Vala.Property) {
 			var prop = (Vala.Property) sym;
-			result.concat (symbol_lookup_inherited (prop.property_type.data_type, name, prefix_match));
+			result.concat (symbol_lookup_inherited_for_type (prop.property_type, name, prefix_match));
 		} else if (sym is Vala.Parameter) {
 			var fp = (Vala.Parameter) sym;
-			result.concat (symbol_lookup_inherited (fp.variable_type.data_type, name, prefix_match));
+			result.concat (symbol_lookup_inherited_for_type (fp.variable_type, name, prefix_match));
 		}
 
 		return result;