[vala/0.40] vala: Don't process initializer of parameter if error is set

[Rico Tzschichholz <ricotz src gnome org>]

commit ffc82b9edcf5b8136fb4daa9f0e0dc910f1de76e
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Tue Feb 18 16:20:42 2020 +0100

    vala: Don't process initializer of parameter if error is set
    
    This caused criticals like:
    
      vala_data_type_compatible: assertion 'self != NULL' failed
      vala_code_node_to_string: assertion 'self != NULL' failed

 tests/Makefile.am                             | 1 +
 tests/semantic/parameter-default-invalid.test | 7 +++++++
 vala/valaparameter.vala                       | 2 +-
 3 files changed, 9 insertions(+), 1 deletion(-)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index ece31815b..00cf6f248 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -727,6 +727,7 @@ TESTS = \
        semantic/objectcreation-non-public-constructor.test \
        semantic/objectcreation-unsupported-type.test \
        semantic/parameter-accessibility.test \
+       semantic/parameter-default-invalid.test \
        semantic/parameter-default-type.test \
        semantic/parameter-out-default.test \
        semantic/parameter-params.test \
diff --git a/tests/semantic/parameter-default-invalid.test b/tests/semantic/parameter-default-invalid.test
new file mode 100644
index 000000000..987bc376c
--- /dev/null
+++ b/tests/semantic/parameter-default-invalid.test
@@ -0,0 +1,7 @@
+Invalid Code
+
+void foo (int bar = G) {
+}
+
+void main () {
+}
diff --git a/vala/valaparameter.vala b/vala/valaparameter.vala
index aad777774..0b54aab41 100644
--- a/vala/valaparameter.vala
+++ b/vala/valaparameter.vala
@@ -176,7 +176,7 @@ public class Vala.Parameter : Variable {
                        }
                }
 
-               if (initializer != null) {
+               if (initializer != null && !initializer.error) {
                        if (initializer is NullLiteral
                            && !variable_type.nullable
                            && direction != ParameterDirection.OUT) {