forbid to put variable in initializer of its declaration

This fixes RT #125371. Variables in initializers in subsequent blocks are allowed though.
rakudo · Aug 17, 2015 · 3754356 · 3754356
1 parent ccfb5fb
commit 3754356
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Showing 2 changed files with 14 additions and 5 deletions.
diff --git a/src/Perl6/Grammar.nqp b/src/Perl6/Grammar.nqp
@@ -1233,8 +1233,10 @@ grammar Perl6::Grammar is HLL::Grammar does STD {
         :my $*POD_BLOCK;
         :my $*DOC := $*DECLARATOR_DOCS;
         :my $*LINE_NO := HLL::Compiler.lineof(self.orig(), self.from(), :cache(1));
-        { $*DECLARATOR_DOCS := '' }
         {
+            $*DECLARATOR_DOCS := '';
+            $*VARIABLE        := '' if $*VARIABLE;
+
             if $*PRECEDING_DECL_LINE < $*LINE_NO {
                 $*PRECEDING_DECL_LINE := $*LINE_NO;
                 $*PRECEDING_DECL := $*DECLARAND;
@@ -1951,6 +1953,8 @@ grammar Perl6::Grammar is HLL::Grammar does STD {
         [
         | :dba('infix noun') '&[' ~ ']' <infixish('[]')>
         | <sigil> <twigil>? <desigilname>
+          [ <?{ !$*IN_DECL && $*VARIABLE && $*VARIABLE eq $<sigil> ~ $<twigil> ~ $<desigilname> }>
+            { self.typed_panic: 'X::Syntax::Variable::Initializer', name => $*VARIABLE } ]?
         | <special_variable>
         | <sigil> $<index>=[\d+]                              [<?{ $*IN_DECL }> <.typed_panic: "X::Syntax::Variable::Numeric">]?
         | <sigil> <?[<]> <postcircumfix>                      [<?{ $*IN_DECL }> <.typed_panic('X::Syntax::Variable::Match')>]?
@@ -2259,6 +2263,7 @@ grammar Perl6::Grammar is HLL::Grammar does STD {
 
     token declarator {
         :my $*LEFTSIGIL := '';
+        :my $*VARIABLE := '';
         [
         # STD.pm6 uses <defterm> here, but we need different
         # action methods
@@ -2364,19 +2369,18 @@ grammar Perl6::Grammar is HLL::Grammar does STD {
 
     token variable_declarator {
         :my $*IN_DECL := 'variable';
-        :my $var;
         <variable>
         {
-            $var := $<variable>.Str;
-            $/.CURSOR.add_variable($var);
+            $*VARIABLE := $<variable>.Str;
+            $/.CURSOR.add_variable($*VARIABLE);
             $*IN_DECL := '';
         }
         [
             <.unsp>?
             $<shape>=[
             | '(' ~ ')' <signature>
                 {
-                    my $sigil := nqp::substr($var, 0, 1);
+                    my $sigil := nqp::substr($*VARIABLE, 0, 1);
                     if $sigil eq '&' {
                         self.typed_sorry('X::Syntax::Reserved',
                             reserved => '() shape syntax in routine declarations',

diff --git a/src/core/Exception.pm b/src/core/Exception.pm
@@ -1087,6 +1087,11 @@ my class X::Syntax::Variable::Match does X::Syntax {
     method message() { 'Cannot declare a match variable' }
 }
 
+my class X::Syntax::Variable::Initializer does X::Syntax {
+    has $.name = '<anon>';
+    method message() { "Cannot use variable $!name in declaration to initialize itself" }
+}
+
 
 my class X::Syntax::Variable::Twigil does X::Syntax {
     has $.what = 'variable';