Re: [359] Record - Compact Constructor should not have throws clause

[Vicente Romero]

On the spec side I agree with Tagir. On the compiler error messages I 
will file an issue to check if we can generate a better error message,

Thanks,
Vicente
On 2/10/20 10:23 PM, Tagir Valeev wrote:
Hello!

вт, 11 февр. 2020 г., 10:18 Manoj Palat <manoj.pa...@in.ibm.com 
<mailto:manoj.pa...@in.ibm.com>>:

    Hi,

    consider
    record R(){
             public R throws Exception {}
    }

     From JLS 14 Sec 8.10.4,
    A canonical constructor must not have a throws clause.

    Sec 8.10.5 says
    A compact constructor is a canonical constructor.

    By the above two, it can be inferred that a compact constructor must not 
have a throws clause. However, there is no explicit mention of this restriction 
in Sec 8.10.5 [1]

    I think it would good to add this explicitly in the next version of spec 
(assuming the above is true).


This unambiguously follows from the compact constructor declaration 
production:

/CompactConstructorDeclaration/:
    { /Annotation/ } { /ConstructorModifier/ } /SimpleTypeName/
    /ConstructorBody/

No throws at all here. To me, this is enough and no changes are necessary.

With best regards,
Tagir Valeev.

    
[1]http://cr.openjdk.java.net/~gbierman/jep359/jep359-20200115/specs/records-jls.html#jls-8.10.5
    Regards,
    Manoj.

    Side Note:
    To compare, javac throws errors but not this particular error (may be due 
to error recovery)
    javac14 --enable-preview --release 14 X.java
    X.java:2: error: <identifier> expected
             public R throws Exception {}
                     ^
    X.java:2: error: field declaration must be static
             public R throws Exception {}
                      ^
       (consider replacing field with record component)
    X.java:2: error: invalid method declaration; return type required
             public R throws Exception {}