Here’s what the AST looks like in this case — there is a ParenExpr but it’s
inside a LoadExpr — we’re semantically loading the largest sub-expression
that’s an lvalue, which here is ‘(x)’ not ‘x’:
(assign_expr
(declref_expr type='@lvalue Int' accessKind=write location=x.swift:3:1
range=[x.swift:3:1 - line:3:1] decl=x.(file).v@x.swift:1:5 direct_to_storage
function_ref=unapplied specialized=no)
(load_expr implicit type='(Int)' location=x.swift:3:6
range=[x.swift:3:5 - line:3:7]
(paren_expr type='(@lvalue Int)' accessKind=read location=x.swift:3:6
range=[x.swift:3:5 - line:3:7]
(declref_expr type='@lvalue Int' accessKind=read
location=x.swift:3:6 range=[x.swift:3:6 - line:3:6] decl=x.(file).v@x.swift:1:5
direct_to_storage function_ref=unapplied specialized=no)))))))
Slava
> On Apr 6, 2017, at 4:02 PM, Halen Wooten via swift-dev <swift-dev@swift.org>
> wrote:
>
> Hi Jordan,
>
> Thanks for your reply. I tried the `dyn_cast<ParenExpr>(src)`, but it
> gives me null. Here's what I've added:
>
> bool TypeChecker::diagnoseSelfAssignment(const Expr *E) {
>
> ...
>
> auto src = AE->getSrc();
> auto parenSrc = dyn_cast<ParenExpr>(src);
> if (parenSrc)
> return false;
>
> ...
>
> }
>
>
>
> On Thu, Apr 6, 2017 at 6:49 PM, Jordan Rose <jordan_r...@apple.com> wrote:
>> Hi, Halen. Welcome to the compiler. :-) What you're seeing is that we don't
>> usually use C++'s normal RTTI mechanism, but instead go with a "Kind" field
>> that's checked by the custom 'cast', 'dyn_cast', and 'isa' functions. (More
>> information in the LLVM Programmer's Manual.) The debugger doesn't know
>> about this, so it just always shows the base class to be conservative. If
>> you're debugging, you can call dump() to see what kind of Expr it really is,
>> and then cast the pointer down to the right type as needed. In your actual
>> code, you can check `isa<ParenExpr>(src)`, or `dyn_cast<ParenExpr>(src)` if
>> you then need to manipulate the ParenExpr.
>>
>> Hope that helps,
>> Jordan
>>
>>
>> On Apr 6, 2017, at 15:30, Halen Wooten via swift-dev <swift-dev@swift.org>
>> wrote:
>>
>> Hi swift devs,
>>
>> I'm working on SR-4464 to learn how to contribute to Swift. I think I
>> have the solution, but I'm getting unexpected results.
>>
>> I'm using the swift repl within Xcode for testing. Here's my test code.
>>
>> var name = "name"
>> name = (name)
>>
>> In TypeChecker::diagnoseSelfAssignment in CSDiag.cpp, the src of the
>> AssignExpr is a plain Expr *, but I would expect it to be a ParenExpr
>> *. Could someone help me figure out what's happening?
>>
>> Thanks,
>> Halen
>> _______________________________________________
>> swift-dev mailing list
>> swift-dev@swift.org
>> https://lists.swift.org/mailman/listinfo/swift-dev
>>
>>
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