My attempt to implement "no strict;"

grammar.patch

diff --git a/src/Perl6/Grammar.nqp b/src/Perl6/Grammar.nqp
index 83f1578..9ecaffc 100644
--- a/src/Perl6/Grammar.nqp
+++ b/src/Perl6/Grammar.nqp
@@ -280,8 +280,11 @@ role STD {
             my $name := $varast.name;
             if $name ne '%_' && $name ne '@_' && !$*W.is_lexical($name) {
                 if $var<sigil> ne '&' {
-                    my @suggestions := $*W.suggest_lexicals($name);
-                    $*W.throw($var, ['X', 'Undeclared'], symbol => $varast.name(), suggestions => @suggestions);
+                    my $decl := nqp::clone($varast);
+                    $decl.decl('contvar');
+                    $*W.install_lexical_symbol($*UNIT, $name, $decl);
+#                    my @suggestions := $*W.suggest_lexicals($name);
+#                    $*W.throw($var, ['X', 'Undeclared'], symbol => $varast.name(), suggestions => @suggestions);
                 }
                 else {
                     $var.CURSOR.add_mystery($varast.name, $var.to, 'var');

runnit.sh

$ ./perl6-j -e '$blerg = 42'
Cannot modify an immutable value
  in block  at -e:1
  in any eval at gen/jvm/stage2/NQPHLL.nqp:1084
  in any command_eval at gen/jvm/stage2/NQPHLL.nqp:1184
  in any command_eval at src/Perl6/Compiler.nqp:17
$ ./perl6-j --target=ast -e '$blerg = 42'
- QAST::CompUnit
  - QAST::Block $blerg = 42
    - QAST::Var(local __args__ :decl(param))
    - QAST::Stmts
    - QAST::Op(call)
      - QAST::Block 
        - QAST::Stmts
          - QAST::Var(lexical GLOBALish :decl(static))
          - QAST::Var(lexical EXPORT :decl(static))
          - QAST::Var(lexical $?PACKAGE :decl(static))
          - QAST::Var(lexical ::?PACKAGE :decl(static))
          - QAST::Var(lexical $_ :decl(contvar))
          - QAST::Var(lexical $/ :decl(contvar))
          - QAST::Var(lexical $! :decl(contvar))
          - QAST::Var(lexical $blerg :decl(static))
          - QAST::Var(lexical $=pod :decl(static))
          - QAST::Var(lexical !UNIT_MARKER :decl(static))
        - QAST::VM
          [loadlibs]
            - nqp_group nqp_ops perl6_ops bit_ops math_ops trans_ops io_ops obscure_ops os file sys_ops nqp_bigint_ops nqp_dyncall_ops
          [jvm]
            - QAST::Op(null)
        - QAST::Stmt
          - QAST::Op(bind)
            - QAST::Var(local ctxsave :decl(var))
            - QAST::Var(contextual $*CTXSAVE)
          - QAST::Op(unless)
            - QAST::Op(isnull)
              - QAST::Var(local ctxsave)
            - QAST::Op(if)
              - QAST::Op(can)
                - QAST::Var(local ctxsave)
                - QAST::SVal(ctxsave)
              - QAST::Op(callmethod ctxsave)
                - QAST::Var(local ctxsave)
        - QAST::Stmts
          - QAST::WVal(Array)
          - QAST::Stmts $blerg = 42
            - QAST::Stmt
              - QAST::Op(p6store) =
                - QAST::Var(lexical $blerg) $blerg
                - QAST::Want 42
                  - QAST::WVal(Int)
                  - Ii
                  - QAST::IVal(42)