[Mono-bugs] [Bug 643456] New: gmcs fails to infer generic type arguments when the "source" type is a generic constraint

[bugzilla_noreply at novell.com]

https://bugzilla.novell.com/show_bug.cgi?id=643456

https://bugzilla.novell.com/show_bug.cgi?id=643456#c0


           Summary: gmcs fails to infer generic type arguments when the
                    "source" type is a generic constraint
    Classification: Mono
           Product: Mono: Compilers
           Version: 2.6.x
          Platform: x86-64
        OS/Version: Linux
            Status: NEW
          Severity: Normal
          Priority: P5 - None
         Component: C#
        AssignedTo: mono-bugs at lists.ximian.com
        ReportedBy: david at dasz.at
         QAContact: mono-bugs at lists.ximian.com
          Found By: ---
           Blocker: ---


User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US)
AppleWebKit/534.3 (KHTML, like Gecko) Chrome/6.0.472.63 Safari/534.3


using System.Collections.Generic;
using System.Linq;

class ListWrapper<TEntry, TEntryCollection>
        where TEntry : class
        where TEntryCollection : IList<TEntry>
{
        public IEnumerable<TEntry> Fail(TEntryCollection subject) {
                return subject.Where(e => e != null); // error CS0411: The type
arguments for method `System.Linq.Enumerable.Where<TSource>(this
System.Collections.Generic.IEnumerable<TSource>,
System.Func<TSource,int,bool>)' cannot be inferred from the usage. Try
specifying the type arguments explicitly
        }

        public IEnumerable<TEntry> NoFail(IList<TEntry> subject) {
                return subject.Where(e => e != null);
        }
}



Reproducible: Always

Steps to Reproduce:
1. try to build the included source

Actual Results:  
The code fails to compile. gmcs fails to infer the type argument for the
Where() in Fail(TEntryCollection):

error CS0411: The type arguments for method
`System.Linq.Enumerable.Where<TSource>(this
System.Collections.Generic.IEnumerable<TSource>,
System.Func<TSource,int,bool>)' cannot be inferred from the usage. Try
specifying the type arguments explicitly


Expected Results:  
The code compiles under MS' CSC.exe from VS2010 (both using langversion=3 and
with default settings)

This seems to be a continuation of bug 599449.

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