[vala/staging: 2/2] codegen: Method needs to throw error if their base method does

[Rico Tzschichholz <ricotz src gnome org>]

commit fec9fd6c30e5571565010028f705f6a0ddb945da
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Sat Jan 27 13:23:53 2018 +0100

    codegen: Method needs to throw error if their base method does
    
    https://bugzilla.gnome.org/show_bug.cgi?id=614294

 tests/Makefile.am            |    1 +
 tests/methods/bug614294.test |   13 +++++++++++++
 vala/valamethod.vala         |   13 +++++++++++--
 3 files changed, 25 insertions(+), 2 deletions(-)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index aba0612..d1bd872 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -78,6 +78,7 @@ TESTS = \
        methods/bug598738.vala \
        methods/bug599892.vala \
        methods/bug613483.vala \
+       methods/bug614294.test \
        methods/bug615450.test \
        methods/bug620673.vala \
        methods/bug622570.vala \
diff --git a/tests/methods/bug614294.test b/tests/methods/bug614294.test
new file mode 100644
index 0000000..fe089d3
--- /dev/null
+++ b/tests/methods/bug614294.test
@@ -0,0 +1,13 @@
+Invalid Code
+
+interface IFoo : Object {
+       public abstract void foo () throws Error;
+}
+
+class Bar : Object, IFoo {
+       public virtual void foo () {
+       }
+}
+
+void main () {
+}
diff --git a/vala/valamethod.vala b/vala/valamethod.vala
index 66c131b..c5ea230 100644
--- a/vala/valamethod.vala
+++ b/vala/valamethod.vala
@@ -386,10 +386,19 @@ public class Vala.Method : Subroutine, Callable {
                        return false;
                }
 
+               var error_types = get_error_types ();
+               var base_error_types = base_method.get_error_types ();
+
+               // method must throw error if the base method does
+               if (error_types.size == 0 && base_error_types.size > 0) {
+                       invalid_match = "missing error type";
+                       return false;
+               }
+
                /* this method may throw less but not more errors than the base method */
-               foreach (DataType method_error_type in get_error_types ()) {
+               foreach (DataType method_error_type in error_types) {
                        bool match = false;
-                       foreach (DataType base_method_error_type in base_method.get_error_types ()) {
+                       foreach (DataType base_method_error_type in base_error_types) {
                                if (method_error_type.compatible (base_method_error_type)) {
                                        match = true;
                                        break;