[vala/0.36] vala: Improve error output of mismatching overriding methods

[Rico Tzschichholz <ricotz src gnome org>]

commit f309925984f0ace9fe95d134f05b57f4eea96be5
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Mon Nov 27 19:46:20 2017 +0100

    vala: Improve error output of mismatching overriding methods
    
    Include the prototype-string of base-method for easier error finding.

 vala/valamethod.vala |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)
---
diff --git a/vala/valamethod.vala b/vala/valamethod.vala
index 1312b17..1778e77 100644
--- a/vala/valamethod.vala
+++ b/vala/valamethod.vala
@@ -563,7 +563,8 @@ public class Vala.Method : Subroutine, Callable {
                                string invalid_match;
                                if (!compatible (base_method, out invalid_match)) {
                                        error = true;
-                                       Report.error (source_reference, "overriding method `%s' is 
incompatible with base method `%s': %s.".printf (get_full_name (), base_method.get_full_name (), 
invalid_match));
+                                       var base_method_type = new MethodType (base_method);
+                                       Report.error (source_reference, "overriding method `%s' is 
incompatible with base method `%s': %s.".printf (get_full_name (), type_to_prototype_string 
(base_method_type), invalid_match));
                                        return;
                                }
 
@@ -609,7 +610,8 @@ public class Vala.Method : Subroutine, Callable {
                                                string invalid_match = null;
                                                if (!compatible (base_method, out invalid_match)) {
                                                        error = true;
-                                                       Report.error (source_reference, "overriding method 
`%s' is incompatible with base method `%s': %s.".printf (get_full_name (), base_method.get_full_name (), 
invalid_match));
+                                                       var base_method_type = new MethodType (base_method);
+                                                       Report.error (source_reference, "overriding method 
`%s' is incompatible with base method `%s': %s.".printf (get_full_name (), type_to_prototype_string 
(base_method_type), invalid_match));
                                                        return;
                                                }
                                                
@@ -621,7 +623,7 @@ public class Vala.Method : Subroutine, Callable {
                }
 
                if (base_interface_type != null) {
-                       Report.error (source_reference, "%s: no suitable interface method found to 
implement".printf (get_full_name ()));
+                       Report.error (source_reference, "`%s': no suitable interface method found to 
implement".printf (get_full_name ()));
                }
        }
 
@@ -776,7 +778,7 @@ public class Vala.Method : Subroutine, Callable {
                                return false;
                        }
                } else if (overrides && base_method == null) {
-                       Report.error (source_reference, "%s: no suitable method found to override".printf 
(get_full_name ()));
+                       Report.error (source_reference, "`%s': no suitable method found to override".printf 
(get_full_name ()));
                } else if ((is_abstract || is_virtual || overrides) && access == SymbolAccessibility.PRIVATE) 
{
                        error = true;
                        Report.error (source_reference, "Private member `%s' cannot be marked as override, 
virtual, or abstract".printf (get_full_name ()));