www.digitalmars.com         C & C++   DMDScript  

digitalmars.D - Wondering about =?UTF-8?Q?errors=E2=80=A6?=

reply Russel Winder <russel winder.org.uk> writes:
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Using rdmd, it appears that the first error in the code can lead the
parsing and template handling of everything following to be wrong. I
keep finding that I am getting spurious errors about things nothing to
do with the actual error, that simply go away when the real error is
fixed. This would imply that most errors reported are generally
spurious?

--=20
Russel.
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D
Dr Russel Winder      t: +44 20 7585 2200   voip: sip:russel.winder ekiga.n=
et
41 Buckmaster Road    m: +44 7770 465 077   xmpp: russel winder.org.uk
London SW11 1EN, UK   w: www.russel.org.uk  skype: russel_winder
May 27 2013
next sibling parent reply "Adam D. Ruppe" <destructionator gmail.com> writes:
Yeah, me too.

I take a working program and add "gf" to the middle of it. Here's 
the errors:

base.d(2143): Error: found '{' when expecting ';' following 
statement
base.d(2168): Error: unexpected ( in declarator
base.d(2168): Error: basic type expected, not "div"
base.d(2168): Error: found '"div"' when expecting ')'
base.d(2168): Error: no identifier for declarator 
div.addChild(int)
base.d(2168): Error: semicolon expected following function 
declaration
base.d(2168): Error: Declaration expected, not ','
base.d(2177): Error: Declaration expected, not 'if'
base.d(2179): Error: no identifier for declarator qrUrl
base.d(2180): Error: unrecognized declaration


OK.... now let's add a semicolon to it. Prepare yourself, here's 
what dmd gives me now:

base.d(2141): Error: undefined identifier gf, did you mean 
template to(T)?
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/format.d(1723): 
Error: template std.format.formatRange does not match any 
function template declaration. Candidates are:
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/format.d(1982):  
       std.format.formatRange(Writer, T, Char)(ref Writer w, ref T 
val, ref FormatSpec!(Char) f) if (isInputRange!(T))
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/format.d(1723): 
Error: template std.format.formatRange(Writer, T, Char)(ref 
Writer w, ref T val, ref FormatSpec!(Char) f) if 
(isInputRange!(T)) cannot deduce template function from argument 
types !()(Appender!(string),immutable(wchar)[],FormatSpec!(char))
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/conv.d(100): 
Error: template instance 
std.format.formatValue!(Appender!(string), immutable(wchar)[], 
char) error instantiating
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/conv.d(807):     
    instantiated from here: toStr!(string, immutable(wchar)[])
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/conv.d(274):     
    instantiated from here: toImpl!(string, immutable(wchar)[])
arsd/characterencodings.d(75):        instantiated from here: 
to!(immutable(wchar)[])
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/conv.d(807): 
Error: template instance std.conv.toStr!(string, 
immutable(wchar)[]) error instantiating
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/conv.d(274):     
    instantiated from here: toImpl!(string, immutable(wchar)[])
arsd/characterencodings.d(75):        instantiated from here: 
to!(immutable(wchar)[])
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/conv.d(274): 
Error: template instance std.conv.toImpl!(string, 
immutable(wchar)[]) error instantiating
arsd/characterencodings.d(75):        instantiated from here: 
to!(immutable(wchar)[])
arsd/characterencodings.d(75): Error: template instance 
std.conv.to!(string).to!(immutable(wchar)[]) error instantiating
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(1718): 
Error: template 
std.array.Appender!(immutable(dchar)[]).Appender.put does not 
match any function template declaration. Candidates are:
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(2305):   
      std.array.Appender!(immutable(dchar)[]).Appender.put(U)(U 
item) if (isImplicitlyConvertible!(U, T) || isSomeChar!(T) && 
isSomeChar!(U))
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(2325):   
      
std.array.Appender!(immutable(dchar)[]).Appender.put(Range)(Range 
items) if (isInputRange!(Unqual!(Range)) && !isInputRange!(Range))
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(2334):   
      
std.array.Appender!(immutable(dchar)[]).Appender.put(Range)(Range 
items) if (isInputRange!(Range) && 
is(typeof(Appender.init.put(items.front))))
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(2305): 
Error: template 
std.array.Appender!(immutable(dchar)[]).Appender.put cannot 
deduce template function from argument types 
!()(immutable(dchar)[])
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(1719): 
Error: template 
std.array.Appender!(immutable(dchar)[]).Appender.put does not 
match any function template declaration. Candidates are:
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(2305):   
      std.array.Appender!(immutable(dchar)[]).Appender.put(U)(U 
item) if (isImplicitlyConvertible!(U, T) || isSomeChar!(T) && 
isSomeChar!(U))
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(2325):   
      
std.array.Appender!(immutable(dchar)[]).Appender.put(Range)(Range 
items) if (isInputRange!(Unqual!(Range)) && !isInputRange!(Range))
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(2334):   
      
std.array.Appender!(immutable(dchar)[]).Appender.put(Range)(Range 
items) if (isInputRange!(Range) && 
is(typeof(Appender.init.put(items.front))))
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(2305): 
Error: template 
std.array.Appender!(immutable(dchar)[]).Appender.put cannot 
deduce template function from argument types 
!()(immutable(dchar)[])
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(1720): 
Error: template std.array.replaceInto does not match any function 
template declaration. Candidates are:
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(1729):   
      std.array.replaceInto(E, Sink, R1, R2)(Sink sink, E[] 
subject, R1 from, R2 to) if (isOutputRange!(Sink, E) && 
isDynamicArray!(E[]) && isForwardRange!(R1) && 
isForwardRange!(R2) && (hasLength!(R2) || isSomeString!(R2)))
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/array.d(1720): 
Error: template std.array.replaceInto(E, Sink, R1, R2)(Sink sink, 
E[] subject, R1 from, R2 to) if (isOutputRange!(Sink, E) && 
isDynamicArray!(E[]) && isForwardRange!(R1) && 
isForwardRange!(R2) && (hasLength!(R2) || isSomeString!(R2))) 
cannot deduce template function from argument types 
!()(Appender!(immutable(dchar)[]),immutable(dchar)[],immutable(dchar)[],immutable(dchar)[])
arsd/html.d(1995): Error: template instance 
std.array.replace!(immutable(dchar), immutable(dchar)[], 
immutable(dchar)[]) error instantiating
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/range.d(608): 
Error: static assert  "Cannot put a immutable(dchar) into a 
Appender!(immutable(dchar)[])"
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/format.d(1691):  
       instantiated from here: put!(Appender!(immutable(dchar)[]), 
immutable(dchar))
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/format.d(2079):  
       instantiated from here: 
formatValue!(Appender!(immutable(dchar)[]), immutable(dchar), 
dchar)
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/format.d(1723):  
       instantiated from here: 
formatRange!(Appender!(immutable(dchar)[]), immutable(dchar)[], 
dchar)
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/format.d(2863):  
       ... (1 instantiations, -v to show) ...
/home/me/d/dmd2/linux/bin32/../../src/phobos/std/format.d(415):   
      instantiated from here: 
formatGeneric!(Appender!(immutable(dchar)[]), immutable(dchar)[], 
dchar)
arsd/html.d(2047):        instantiated from here: 
formattedWrite!(Appender!(immutable(dchar)[]), dchar, 
immutable(dchar)[],immutable(dchar)[],immutable(dchar)[],immutable(dchar)[],immutable(dchar)[])
make: *** [all] Error 1




I'm not making that up. dmd has been doing it for several 
releases now - I noticed it started up when I started using 
ctRegex in cgi.d and keep hoping it will go away with each 
release.

The only relevant line there is:

base.d(2141): Error: undefined identifier gf, did you mean 
template to(T)?


Remember, all I changed in this whole (working) program was the 
addition of "gf;" in the middle of it.
May 27 2013
next sibling parent reply Andrei Alexandrescu <SeeWebsiteForEmail erdani.org> writes:
On 5/27/13 7:51 AM, Adam D. Ruppe wrote:
 Yeah, me too.

 I take a working program and add "gf" to the middle of it. Here's the
 errors:

I'd say that deserves a bugzilla entry. Andrei
May 27 2013
parent Timon Gehr <timon.gehr gmx.ch> writes:
On 05/27/2013 10:12 PM, Andrei Alexandrescu wrote:
 On 5/27/13 7:51 AM, Adam D. Ruppe wrote:
 Yeah, me too.

 I take a working program and add "gf" to the middle of it. Here's the
 errors:

I'd say that deserves a bugzilla entry. Andrei

I have been trying to reduce a similar issue. What appears to trigger the message is that DMD sometimes evaluates isInputRange!string as false.
May 30 2013
prev sibling parent Rainer Schuetze <r.sagitario gmx.de> writes:
On 27.05.2013 13:51, Adam D. Ruppe wrote:
 Yeah, me too.

 I take a working program and add "gf" to the middle of it. Here's the
 errors:

 base.d(2143): Error: found '{' when expecting ';' following statement
 base.d(2168): Error: unexpected ( in declarator
 base.d(2168): Error: basic type expected, not "div"
 base.d(2168): Error: found '"div"' when expecting ')'
 base.d(2168): Error: no identifier for declarator div.addChild(int)
 base.d(2168): Error: semicolon expected following function declaration
 base.d(2168): Error: Declaration expected, not ','
 base.d(2177): Error: Declaration expected, not 'if'
 base.d(2179): Error: no identifier for declarator qrUrl
 base.d(2180): Error: unrecognized declaration


 OK.... now let's add a semicolon to it. Prepare yourself, here's what
 dmd gives me now:

 base.d(2141): Error: undefined identifier gf, did you mean template to(T)?
 /home/me/d/dmd2/linux/bin32/../../src/phobos/std/format.d(1723): Error:
 template std.format.formatRange does not match any function template

 formattedWrite!(Appender!(immutable(dchar)[]), dchar,
 immutable(dchar)[],immutable(dchar)[],immutable(dchar)[],immutable(dchar)[],immutable(dchar)[])

 make: *** [all] Error 1

I think most of these floods of errors come from not wanting to instantiate templates once any (completely unrelated) error has been shown. This has improved, but I just found two instances of that in mtype.c: if (global.errors) return new ErrorExp(); // TemplateInstance::semantic() will fail anyway The mechanism of not showing errors if they contain ErrorExp seems to not work in that case, but I think not even trying to do the instantiation is unreasonable (just stopping compilation would be better).
May 27 2013
prev sibling next sibling parent "Maxim Fomin" <maxim maxim-fomin.ru> writes:
On Monday, 27 May 2013 at 11:51:45 UTC, Adam D. Ruppe wrote:
 Yeah, me too.
 base.d(2141): Error: undefined identifier gf, did you mean 
 template to(T)?
 /home/me/d/dmd2/linux/bin32/../../src/phobos/std/format.d(1723): 
 Error: template std.format.formatRange does not match any 
 function template declaration. Candidates are:
 /home/me/d/dmd2/linux/bin32/../../src/phobos/std/format.d(1982):
       std.format.formatRange(Writer, T, Char)(ref Writer w, ref 
 <screens of errors>
 make: *** [all] Error 1

"C++ is the only language where error message can be bigger than the program". Unfortunately this happens sometimes in D too.
May 27 2013
prev sibling next sibling parent Russel Winder <russel winder.org.uk> writes:
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Mon, 2013-05-27 at 13:51 +0200, Adam D. Ruppe wrote:
 Yeah, me too.

Phew, I'm so pleased it is not just me! My problem was forgetting an import. I am using std.array.split in one function and std.stdio.writef in a completely separate function. With split imported correctly everything compiles and runs as expected and required. Forgetting the import of split(*), I get: wc.d(11): Error: undefined identifier 'split' /usr/include/dmd/phobos/std/range.d(611): Error: static assert "Cannot put= a char[] into a Appender!(string)" /usr/include/dmd/phobos/std/format.d(1436): instantiated from here: = put!(Appender!(string), char[]) /usr/include/dmd/phobos/std/format.d(1338): instantiated from here: = formatUnsigned!(Appender!(string), char) /usr/include/dmd/phobos/std/format.d(1312): instantiated from here: = formatIntegral!(Appender!(string), ulong, char) /usr/include/dmd/phobos/std/conv.d(100): ... (13 instantiations, -v = to show) ... /usr/include/dmd/phobos/std/stdio.d(1784): instantiated from here: w= ritefln!(char, immutable(int),immutable(int),immutable(int),string) wc.d(18): instantiated from here: writefln!(string,immutable(int),im= mutable(int),immutable(int),string) Which definitely results in a ***WTF***. How can a missing import cause this insane error report? If I use -v it looks even worse. (*) I am not a fan of importing all symbols from a module, so I always use selective imports. Whilst Python has no problem with imports and name spaces, Java, Scala, Groovy and D have horrible problems since the import imports into the current namespace. Obviously C++ is just a problem here due to textual inclusion rather than a module system. --=20 Russel. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D Dr Russel Winder t: +44 20 7585 2200 voip: sip:russel.winder ekiga.n= et 41 Buckmaster Road m: +44 7770 465 077 xmpp: russel winder.org.uk London SW11 1EN, UK w: www.russel.org.uk skype: russel_winder
May 27 2013
prev sibling next sibling parent reply Walter Bright <newshound2 digitalmars.com> writes:
On 5/27/2013 4:32 AM, Russel Winder wrote:
 Using rdmd, it appears that the first error in the code can lead the
 parsing and template handling of everything following to be wrong. I
 keep finding that I am getting spurious errors about things nothing to
 do with the actual error, that simply go away when the real error is
 fixed. This would imply that most errors reported are generally
 spurious?

The usual approach to handling errors in a compiler is to guess at what the user actually meant, repair the AST according to that guess, then continue on. Unfortunately, the guess is usually wrong and the result is cascaded errors, of which only the first is meaningful. DMD has been gradually switching over to a more novel approach, one that I haven't seen elsewhere. Once an error is discovered, the AST is marked as "erroneous". That erroneous state propagates upwards to the root of the AST, and that any AST that relies on an erroneous AST is itself erroneous, and no further error messages are emitted for it. The result should be that only "original sin" errors are reported. This has already resulted in a great reduction of spurious error messages, but clearly we have more work to do.
May 27 2013
parent Jacob Carlborg <doob me.com> writes:
On 2013-05-27 22:32, Walter Bright wrote:

 The usual approach to handling errors in a compiler is to guess at what
 the user actually meant, repair the AST according to that guess, then
 continue on. Unfortunately, the guess is usually wrong and the result is
 cascaded errors, of which only the first is meaningful.

 DMD has been gradually switching over to a more novel approach, one that
 I haven't seen elsewhere. Once an error is discovered, the AST is marked
 as "erroneous". That erroneous state propagates upwards to the root of
 the AST, and that any AST that relies on an erroneous AST is itself
 erroneous, and no further error messages are emitted for it.

 The result should be that only "original sin" errors are reported.

 This has already resulted in a great reduction of spurious error
 messages, but clearly we have more work to do.

Clang is still a lot better on this than DMD. Take this simple example: void main () { int a = 3 // Missing semicolon, line 3 int b = 5; } Compiling this with DMD gives the following error: main.d(4): Error: semicolon expected, not 'int' Where's Clang gives the following error for the same code: main.c:3:11: error: expected ';' at end of declaration int a = 3 ^ ; 1 error generated. It knows that you most likely meant to put the semicolon on the end of line 3 instead of the beginning of line 4. It also don't give completely false spell checking suggestion, like Adam showed: Error: undefined identifier gf, did you mean template to(T) -- /Jacob Carlborg
May 28 2013
prev sibling next sibling parent Timothee Cour <thelastmammoth gmail.com> writes:
--e89a8ff2502ad384ae04ddc258fa
Content-Type: text/plain; charset=ISO-8859-1

I posted bugzilla entry:
http://d.puremagic.com/issues/show_bug.cgi?id=10177a few days ago. In
short, it says: 'why not just stop semantic3 passes at
1st error occurence' ?

Other entries related to irrelevant error messages that I've recently
reported:10169 , 10141, 10177.


On Mon, May 27, 2013 at 11:43 PM, Rainer Schuetze <r.sagitario gmx.de>wrote:

 On 27.05.2013 13:51, Adam D. Ruppe wrote:

 Yeah, me too.

 I take a working program and add "gf" to the middle of it. Here's the
 errors:

 base.d(2143): Error: found '{' when expecting ';' following statement
 base.d(2168): Error: unexpected ( in declarator
 base.d(2168): Error: basic type expected, not "div"
 base.d(2168): Error: found '"div"' when expecting ')'
 base.d(2168): Error: no identifier for declarator div.addChild(int)
 base.d(2168): Error: semicolon expected following function declaration
 base.d(2168): Error: Declaration expected, not ','
 base.d(2177): Error: Declaration expected, not 'if'
 base.d(2179): Error: no identifier for declarator qrUrl
 base.d(2180): Error: unrecognized declaration


 OK.... now let's add a semicolon to it. Prepare yourself, here's what
 dmd gives me now:

 base.d(2141): Error: undefined identifier gf, did you mean template to(T)?
 /home/me/d/dmd2/linux/bin32/..**/../src/phobos/std/format.d(**1723):
 Error:
 template std.format.formatRange does not match any function template

formattedWrite!(Appender!(**immutable(dchar)[]), dchar,
 immutable(dchar)[],immutable(**dchar)[],immutable(dchar)[],**
 immutable(dchar)[],immutable(**dchar)[])

 make: *** [all] Error 1

instantiate templates once any (completely unrelated) error has been shown. This has improved, but I just found two instances of that in mtype.c: if (global.errors) return new ErrorExp(); // TemplateInstance::semantic() will fail anyway The mechanism of not showing errors if they contain ErrorExp seems to not work in that case, but I think not even trying to do the instantiation is unreasonable (just stopping compilation would be better).

--e89a8ff2502ad384ae04ddc258fa Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable <div>I posted bugzilla entry:=A0<a href=3D"http://d.puremagic.com/issues/sh= ow_bug.cgi?id=3D10177">http://d.puremagic.com/issues/show_bug.cgi?id=3D1017= 7</a> a few days ago. In short, it says: &#39;why not just stop semantic3 p= asses at 1st error occurence&#39; ?</div> <div><br></div><div>Other entries related to irrelevant error messages that= I&#39;ve recently reported:10169 , 10141, 10177.</div><div><br></div><div>= <div><br><div class=3D"gmail_quote">On Mon, May 27, 2013 at 11:43 PM, Raine= r Schuetze <span dir=3D"ltr">&lt;<a href=3D"mailto:r.sagitario gmx.de" targ= et=3D"_blank">r.sagitario gmx.de</a>&gt;</span> wrote:<br> <blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p= x #ccc solid;padding-left:1ex"><div class=3D"im"><br> <br> On 27.05.2013 13:51, Adam D. Ruppe wrote:<br> <blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p= x #ccc solid;padding-left:1ex"> Yeah, me too.<br> <br> I take a working program and add &quot;gf&quot; to the middle of it. Here&#= 39;s the<br> errors:<br> <br> base.d(2143): Error: found &#39;{&#39; when expecting &#39;;&#39; following= statement<br> base.d(2168): Error: unexpected ( in declarator<br> base.d(2168): Error: basic type expected, not &quot;div&quot;<br> base.d(2168): Error: found &#39;&quot;div&quot;&#39; when expecting &#39;)&= #39;<br> base.d(2168): Error: no identifier for declarator div.addChild(int)<br> base.d(2168): Error: semicolon expected following function declaration<br> base.d(2168): Error: Declaration expected, not &#39;,&#39;<br> base.d(2177): Error: Declaration expected, not &#39;if&#39;<br> base.d(2179): Error: no identifier for declarator qrUrl<br> base.d(2180): Error: unrecognized declaration<br> <br> <br> OK.... now let&#39;s add a semicolon to it. Prepare yourself, here&#39;s wh= at<br> dmd gives me now:<br> <br> base.d(2141): Error: undefined identifier gf, did you mean template to(T)?<= br> /home/me/d/dmd2/linux/bin32/..<u></u>/../src/phobos/std/format.d(<u></u>172= 3): Error:<br> template std.format.formatRange does not match any function template<br> </blockquote></div> [...]<div class=3D"im"><br> <blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p= x #ccc solid;padding-left:1ex"> formattedWrite!(Appender!(<u></u>immutable(dchar)[]), dchar,<br> immutable(dchar)[],immutable(<u></u>dchar)[],immutable(dchar)[],<u></u>immu= table(dchar)[],immutable(<u></u>dchar)[])<br> <br> make: *** [all] Error 1<br> <br> </blockquote> <br></div> I think most of these floods of errors come from not wanting to instantiate= templates once any (completely unrelated) error has been shown. This has i= mproved, but I just found two instances of that in mtype.c:<br> <br> =A0 =A0 if (global.errors)<br> =A0 =A0 =A0 =A0 return new ErrorExp(); =A0// TemplateInstance::semantic() w= ill fail anyway<br> <br> The mechanism of not showing errors if they contain ErrorExp seems to not w= ork in that case, but I think not even trying to do the instantiation is un= reasonable (just stopping compilation would be better).<br> </blockquote></div><br></div></div> --e89a8ff2502ad384ae04ddc258fa--
May 28 2013
prev sibling next sibling parent Nick Sabalausky <SeeWebsiteToContactMe semitwist.com> writes:
On Mon, 27 May 2013 13:32:46 -0700
Walter Bright <newshound2 digitalmars.com> wrote:

 On 5/27/2013 4:32 AM, Russel Winder wrote:
 Using rdmd, it appears that the first error in the code can lead the
 parsing and template handling of everything following to be wrong. I
 keep finding that I am getting spurious errors about things nothing
 to do with the actual error, that simply go away when the real
 error is fixed. This would imply that most errors reported are
 generally spurious?

The usual approach to handling errors in a compiler is to guess at what the user actually meant, repair the AST according to that guess, then continue on. Unfortunately, the guess is usually wrong and the result is cascaded errors, of which only the first is meaningful. DMD has been gradually switching over to a more novel approach, one that I haven't seen elsewhere. Once an error is discovered, the AST is marked as "erroneous". That erroneous state propagates upwards to the root of the AST, and that any AST that relies on an erroneous AST is itself erroneous, and no further error messages are emitted for it. The result should be that only "original sin" errors are reported. This has already resulted in a great reduction of spurious error messages, but clearly we have more work to do.

Is this what all the "error gagging" stuff is all about, or is there more to that?
May 28 2013
prev sibling parent "David Nadlinger" <see klickverbot.at> writes:
On Tuesday, 28 May 2013 at 19:10:54 UTC, Nick Sabalausky wrote:
 Is this what all the "error gagging" stuff is all about, or is 
 there
 more to that?

No, error gagging is completely unrelated, it applies to "speculative evaluation" of code. The most obvious example for that is __traits(compiles, ...). David
May 28 2013