[vala/staging] vala: Warn when directly accessing member of silent cast-expression

[Rico Tzschichholz <ricotz src gnome org>]

commit 3049558912c04eea9eefef5b05b5342f0f9f4f10
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Mon Sep 23 15:56:49 2019 +0200

    vala: Warn when directly accessing member of silent cast-expression
    
    "foo as TypeSymbol" may result in `null' and accessing it without check is
    not recommended. If the invocation context provides information that `null'
    is not a possible result then use an unsafe cast "(TypeSymbol) foo".

 vala/valamemberaccess.vala | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/vala/valamemberaccess.vala b/vala/valamemberaccess.vala
index 37eeafb87..ad3f3d0fc 100644
--- a/vala/valamemberaccess.vala
+++ b/vala/valamemberaccess.vala
@@ -343,6 +343,10 @@ public class Vala.MemberAccess : Expression {
                                }
                        }
 
+                       if (inner is CastExpression && ((CastExpression) inner).is_silent_cast) {
+                               Report.warning (source_reference, "Access to possible `null'. Perform a check 
or use an unsafe cast.");
+                       }
+
                        if (inner is MemberAccess || inner is BaseAccess) {
                                base_symbol = inner.symbol_reference;