Complain on placeholders in attr initializers.

Fixes RT #78112. Includes a typed exception, for easy testing.
rakudo · Apr 7, 2015 · c2f531a · c2f531a
1 parent a3b4710
commit c2f531a
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diff --git a/src/Perl6/Actions.nqp b/src/Perl6/Actions.nqp
@@ -6918,6 +6918,12 @@ class Perl6::Actions is HLL::Actions does STDActions {
     # attribute.
     method install_attr_init($/, $attr, $initializer, $block) {
         # Construct signature and anonymous method.
+        if $block.ann('placeholder_sig') {
+            $*W.throw($/, 'X::Placeholder::Attribute',
+                precursor => '1',
+                placeholder => $block.ann('placeholder_sig')[0]<placeholder>,
+            );
+        }
         my @params := [
             hash( is_invocant => 1, nominal_type => $*PACKAGE),
             hash( variable_name => '$_', nominal_type => $*W.find_symbol(['Mu']))

diff --git a/src/core/Exception.pm b/src/core/Exception.pm
@@ -559,6 +559,12 @@ my class X::Placeholder::Mainline is X::Placeholder::Block {
     }
 }
 
+my class X::Placeholder::Attribute is X::Placeholder::Block {
+    method message() {
+        "Cannot use placeholder parameter $.placeholder in an attribute initializer"
+    }
+}
+
 my class X::Undeclared does X::Comp {
     has $.what = 'Variable';
     has $.symbol;