Changes between Initial Version and Version 9 of Ticket #1897


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Timestamp:
Dec 29, 2008 4:35:24 PM (5 years ago)
Author:
simonpj
Comment:

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  • Ticket #1897

    • Property Status changed from new to reopened
    • Property Component changed from Compiler to Compiler (Type checker)
    • Property Summary changed from Type families: type signature rejected to Ambiguous types and rejected type signatures
    • Property Difficulty changed from to Unknown
    • Property Milestone changed from to 6.10 branch
    • Property Owner set to chak
  • Ticket #1897 – Description

    initial v9  
    1 The following programm does not compile: 
     1This ticket collects a bunch of examples where GHC 
     2 * Rejects a function with a type signature but, if the type signature is removed, accepts the function and infers precisely the type that was originally specified. 
     3 * Accepts type signatures that are utterly ambiguous; that is, the function could never be called, or only in the presence of bizarre instance declarations. 
     4 * Rejects definitions that clearly have a unique typing. 
     5 
     6Original example: the following programm does not compile: 
    27 
    38{{{