Bug 15863 - vbnc rejects StreamReader.EndOfStream in loop condition
Summary: vbnc rejects StreamReader.EndOfStream in loop condition
Status: RESOLVED FIXED
Alias: None
Product: Compilers
Classification: Mono
Component: VisualBasic ()
Version: 3.2.x
Hardware: PC Linux
: --- normal
Target Milestone: ---
Assignee: Rolf Bjarne Kvinge [MSFT]
URL:
Depends on:
Blocks:
 
Reported: 2013-10-31 17:52 UTC by Robert Dodier
Modified: 2013-10-31 21:49 UTC (History)
2 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FIXED

Description Robert Dodier 2013-10-31 17:52:51 UTC
I am working with vbnc as built from current Git sources. mono --version reports Mono Runtime Engine version 3.2.5 (master/7516586 Tue Oct 29 22:09:55 EDT 2013), vbnc --version reports Visual Basic.Net Compiler version 0.0.0.5943 (Mono 3.0 - master/4dcc70f). Host is RHEL 6.

vbnc rejects StreamReader.EndOfStream in loop condition, but accepts an equivalent local variable.

vbnc accepts this program:

Imports System
Imports System.IO
Public Module modmain
  Dim f as Object
  Dim eof as Boolean
  Sub Main ()
    f = File.OpenText ("foo.in")
    eof = f.EndOfStream
    Do While Not eof
      Console.WriteLine (f.Readline ())
      eof = f.EndOfStream
    Loop
  End Sub
End Module

vbnc rejects this program:

Imports System
Imports System.IO
Public Module modmain
  Dim f as Object
  Sub Main ()
    f = File.OpenText ("foo.in")
    Do While Not f.EndOfStream
      Console.WriteLine (f.Readline ())
    Loop
  End Sub
End Module

with this message:

$ vbnc tmp1.vb
Visual Basic.Net Compiler version 0.0.0.5943 (Mono 3.0 - master/4dcc70f)
Copyright (C) 2004-2010 Rolf Bjarne Kvinge. All rights reserved.

Missed option: Object_Boolean
/home/ipadmin/tmp/tmp1.vb (5,11)
vbnc : Command line : error VBNC99999: Unexpected error: There has been an internal error in the compiler: 
  at vbnc.Helper.Stop (System.String Message) [0x00017] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/General/Helper.vb:2251 
  at vbnc.Emitter.EmitConversion (Mono.Cecil.TypeReference FromType, Mono.Cecil.TypeReference ToType, vbnc.EmitInfo Info) [0x011af] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/Emit/Emitter.vb:818 
  at vbnc.DoStatement.GenerateCode (vbnc.EmitInfo Info) [0x00096] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/Statements/DoStatement.vb:93 
  at vbnc.CodeBlock.GenerateCode (vbnc.EmitInfo Info) [0x00149] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/Code/CodeBlock.vb:520 
  at vbnc.CodeBlock.GenerateCode (IMethod Method) [0x00060] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/Code/CodeBlock.vb:450 
  at vbnc.MethodBaseDeclaration.GenerateCode (vbnc.EmitInfo Info) [0x000b9] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/General/MethodBaseDeclaration.vb:353 
  at vbnc.MethodDeclaration.GenerateCode (vbnc.EmitInfo Info) [0x00006] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/Members/MethodDeclaration.vb:74 
  at vbnc.SubDeclaration.GenerateCode (vbnc.EmitInfo Info) [0x00045] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/Members/SubDeclaration.vb:98 
  at vbnc.Helper.GenerateCodeCollection (IEnumerable Collection, vbnc.EmitInfo Info) [0x00036] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/General/Helper.vb:2100 
  at vbnc.BaseObjects`1[vbnc.IMember].GenerateCode (vbnc.EmitInfo Info) [0x00000] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/General/BaseObjects`1.vb:75 
  at vbnc.AssemblyDeclaration.Emit (vbnc.TypeDeclaration Type) [0x00006] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/TypeDeclarations/AssemblyDeclaration.vb:129 
  at vbnc.AssemblyDeclaration.Emit () [0x0005e] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/TypeDeclarations/AssemblyDeclaration.vb:633 
  at vbnc.Compiler.Compile () [0x005b2] in /home/ipadmin/mono-git/mono-basic/vbnc/vbnc/source/General/Compiler.vb:543 
Compilation took 00:00:01.1881970
Comment 1 Rolf Bjarne Kvinge [MSFT] 2013-10-31 18:05:24 UTC
What vbnc fails on is the implicitly typed variable. If you declare the variable correctly, vbnc compiles the test code:

  Dim f as StreamReader
Comment 2 Robert Dodier 2013-10-31 18:10:31 UTC
Incidentally, vbnc accepts the same condition (Not f.EndOfStream) in an If
statement.
Comment 3 Robert Dodier 2013-10-31 18:48:28 UTC
I've verified that Dim f as StreamReader makes the problem go away.
Comment 4 Rolf Bjarne Kvinge [MSFT] 2013-10-31 21:49:58 UTC
Fixed.

mono-basic/master: 292b6c6b86d0ec59f552e8d0a4149354d7921f20