diff options
| author | Hans Bolinder <[email protected]> | 2016-11-29 09:37:21 +0100 |
|---|---|---|
| committer | Hans Bolinder <[email protected]> | 2016-12-01 16:07:11 +0100 |
| commit | 91048957f0681dba853f5720d3618aa1c5d0255e (patch) | |
| tree | 6e15b3365bc2ea4b9d7042c1d023f71bb0002f2d /erts/doc | |
| parent | ca29c37928ad36cf4270fb3edffc2cf9752f2ed9 (diff) | |
| download | otp-91048957f0681dba853f5720d3618aa1c5d0255e.tar.gz otp-91048957f0681dba853f5720d3618aa1c5d0255e.tar.bz2 otp-91048957f0681dba853f5720d3618aa1c5d0255e.zip | |
stdilb: Check for bad type constraints in function types
The parser recognizes the 'is_subtype(V, T)' syntax for constraints,
and of course the new 'V :: T' syntax, but other variants result in an
error message. Up to now, the parser and linter have let badly formed
constraints through, and relied upon Dialyzer to emit warnings.
is_subtype/2 cannot easily be taken out from the parser. Not only
would we need find a way to emit a (linter) warning, but there also
needs to be an option for suppressing the linter warning as
compilation with +warnings_as_errors has to work. (Notice that the
abstract format representation for 'V :: T' is the same as for
'is_subtype(V, T)'.)
This correction was triggered by an email from Robert, and Kostis
created pull request 1214 to provide a fix. However, Kostis' fix
disallowed is_subtype() altogether, which breaks backward
compatibility.
As of Erlang/OTP 19.0 (ticket OTP-11879), the 'is_subtype(V, T)' is no
longer documented.
Diffstat (limited to 'erts/doc')
| -rw-r--r-- | erts/doc/src/absform.xml | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/erts/doc/src/absform.xml b/erts/doc/src/absform.xml index ab00d47425..fe8e3b30e7 100644 --- a/erts/doc/src/absform.xml +++ b/erts/doc/src/absform.xml @@ -886,7 +886,7 @@ Rep(Fc) = <c>[Rep(C_1), ..., Rep(C_k)]</c>.</p> <list type="bulleted"> - <item>If C is a constraint <c>is_subtype(V, T)</c> or <c>V :: T</c>, + <item>If C is a constraint <c>V :: T</c>, where <c>V</c> is a type variable and <c>T</c> is a type, then Rep(C) = <c>{type,LINE,constraint,[{atom,LINE,is_subtype},[Rep(V),Rep(T)]]}</c>. |