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digitalmars.D.bugs - [Issue 12871] New: inner function returning pointer to outer context


          Issue ID: 12871
           Summary: inner function returning pointer to outer context
                    local rejected
           Product: D
           Version: D2
          Hardware: x86
                OS: All
            Status: NEW
          Keywords: rejects-valid
          Severity: normal
          Priority: P1
         Component: DMD
          Assignee: nobody puremagic.com
          Reporter: schveiguy yahoo.com

When writing an inner function, or lambda, that will not escape a local for
that function's scope, but instead escapes a local for the enclosing scope, the
compiler rejects it with the message "Error: escaping reference to local"


void foo()
   int a;
   int *dg(){return &a;}

Clearly, a will not escape its scope through dg. Such a function may be used to
modularize parts of the function, and so should not be flagged as invalid. If
the delegate is returned, it should create a closure anyway.

Such constructs are very important to get right because the expected way to
apply certain attributes such as  trusted to an expression inside a  safe
function are via a lambda expression.

Jun 06 2014