Crystal: Regression typeof(sizeof(x)) should receive a type

Created on 13 Feb 2018  路  10Comments  路  Source: crystal-lang/crystal

After upgrading to crystal 0.24.1 from 0.23.1 I can no longer compile the timuckun/crystal-liblmdb shard.

Here's the crystal -v output:

Crystal 0.24.1 (2018-01-27)

LLVM: 5.0.1
Default target: x86_64-apple-macosx

The compilation fails with the following error in src/lmdb/base.cr:112:16:

Error target prget failed to compile:
BUG: sizeof(typeof(x)) at /Users/felix/dev/misc/prget/lib/lmdb/src/lmdb/base.cr:112:16 should receive a type
Crystal::MainVisitor#visit<Crystal::SizeOf>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#visit<Crystal::Assign>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#visit<Crystal::If>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#visit<Crystal::If>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::Call#instantiate<Crystal::Matches, Crystal::Type+, Nil>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in_type<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil), Nil, String, Bool, Bool>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil)>:Array(Crystal::Def+)
Crystal::Call#recalculate:Nil
Crystal::MainVisitor#visit<Crystal::Call>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::Call#instantiate<Crystal::Matches, Crystal::Type+, Nil>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in_type<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil), Nil, String, Bool, Bool>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil)>:Array(Crystal::Def+)
Crystal::Call#recalculate:Nil
Crystal::MainVisitor#visit<Crystal::Call>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::Call#instantiate<Crystal::Matches, Crystal::Type+, Nil>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in_type<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil), Nil, String, Bool, Bool>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil)>:Array(Crystal::Def+)
Crystal::Call#recalculate:Nil
Crystal::MainVisitor#visit<Crystal::Call>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#visit<Crystal::Assign>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::Call#instantiate<Crystal::Matches, Crystal::Type+, Nil>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in_type<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil), Nil, String, Bool, Bool>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil)>:Array(Crystal::Def+)
Crystal::Call#recalculate:Nil
Crystal::MainVisitor#visit<Crystal::Call>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::Call#instantiate<Crystal::Matches, Crystal::Type+, Nil>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in_type<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil), Nil, String, Bool, Bool>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil)>:Array(Crystal::Def+)
Crystal::Call#recalculate:Nil
Crystal::MainVisitor#visit<Crystal::Call>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#visit<Crystal::Block>:(Bool | Nil)
Crystal::MainVisitor#visit<Crystal::Yield>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#visit<Crystal::ExceptionHandler>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::Call#instantiate<Crystal::Matches, Crystal::Type+, Nil>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in_type<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil), Nil, String, Bool, Bool>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil)>:Array(Crystal::Def+)
Crystal::Call#recalculate:Nil
Crystal::MainVisitor#visit<Crystal::Call>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::Call#instantiate<Crystal::Matches, Crystal::Type+, Nil>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in_type<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil), Nil, String, Bool, Bool>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil)>:Array(Crystal::Def+)
Crystal::Call#recalculate:Nil
Crystal::MainVisitor#visit<Crystal::Call>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#visit<Crystal::Assign>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#expand<Crystal::MultiAssign>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#visit<Crystal::Block>:(Bool | Nil)
Crystal::MainVisitor#visit<Crystal::Yield>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#visit<Crystal::ExceptionHandler>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::Call#instantiate<Crystal::Matches, Crystal::Type+, Nil>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in_type<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil), Nil, String, Bool, Bool>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil)>:Array(Crystal::Def+)
Crystal::Call#recalculate:Nil
Crystal::MainVisitor#visit<Crystal::Call>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#visit<Crystal::If>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#visit<Crystal::If>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::Call#instantiate<Crystal::Matches, Crystal::Type+, Nil>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in_type<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil), Nil, String, Bool, Bool>:Array(Crystal::Def+)
Crystal::Call#lookup_matches_in<Crystal::Type+, Array(Crystal::Type+), (Array(Crystal::NamedArgumentType) | Nil)>:Array(Crystal::Def+)
Crystal::Call#recalculate:Nil
Crystal::MainVisitor#visit<Crystal::Call>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::Program#visit_main<Crystal::ASTNode+, Crystal::MainVisitor, Bool, Bool>:Crystal::ASTNode+
Crystal::Program#semantic<Crystal::ASTNode+, Bool>:Crystal::ASTNode+
Crystal::Compiler#compile<Array(Crystal::Compiler::Source), String>:Crystal::Compiler::Result
Crystal::Command#run:(Bool | Crystal::Compiler::Result | IO::FileDescriptor | Nil)
main

Error: you've found a bug in the Crystal compiler. Please open an issue, including source code that will allow us to reproduce the bug: https://github.com/crystal-lang/crystal/issues

The problem also occurs when cloning the shard and running crystal spec(you must have liblmdb installed, eg. using brew install lmdb on macOS).

I tried building a minimal reproduction, but the following code compiles fine on 0.24.1:

x = 1
case x
when Int32, UInt32, Float32, Int64, UInt64, Float64
  size = sizeof(typeof(x))
  puts size
end
bug compiler
Source
picture felixbuenemann

Most helpful comment

Huh, i tried and looks like problem isn't so scary.
basically, test case is

v = nil
if v.nil?
  #
else
  sizeof(typeof(v))
end

in real code it happens because v is an input argument of a method, so usually it is a union or not nil, but sometimes it is called directly with nil.

picture konovod on 21 Mar 2018
👍2

All 10 comments

I tested compilation using 0.24.0 and it works, so regression happened some time after 0.24.0.

felixbuenemann picture felixbuenemann on 13 Feb 2018

This is still broken in 0.24.2.

felixbuenemann picture felixbuenemann on 17 Mar 2018

Same problem with https://github.com/Papierkorb/cannon - works in 0.24.0, broken in 0.24.2, #5807 doesn't fix it. 

BUG: sizeof(typeof(value)) at expanded macro: fast_encode:1:51 should receive a type
konovod picture konovod on 21 Mar 2018

@konovod Have you been able to create a standalone test case?

felixbuenemann picture felixbuenemann on 21 Mar 2018

Huh, i tried and looks like problem isn't so scary.
basically, test case is

v = nil
if v.nil?
  #
else
  sizeof(typeof(v))
end

in real code it happens because v is an input argument of a method, so usually it is a union or not nil, but sometimes it is called directly with nil.

konovod picture konovod on 21 Mar 2018
👍2

I'm having the same problem using @konovod's snippet.

# tmp/bug.cr
v = nil
if v.nil?
  #
else
  sizeof(typeof(v))
end

crystal tmp/bug.cr

BUG: sizeof(typeof(v)) at /Users/scott.pierce/code/crystal/mandelbrot/tmp/bug.cr:5:3 should receive a type
Crystal::MainVisitor#visit<Crystal::SizeOf>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::MainVisitor#visit<Crystal::If>:Bool
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::ASTNode+@Crystal::ASTNode#accept<Crystal::MainVisitor>:Nil
Crystal::Program#visit_main<Crystal::ASTNode+, Crystal::MainVisitor, Bool, Bool>:Crystal::ASTNode+
Crystal::Program#semantic<Crystal::ASTNode+, Bool>:Crystal::ASTNode+
Crystal::Compiler#compile<Array(Crystal::Compiler::Source), String>:Crystal::Compiler::Result
Crystal::Command#run_command<Bool>:Nil
Crystal::Command#run:(Bool | Crystal::Compiler::Result | IO::FileDescriptor | Nil)
main

crystal --version
Crystal 0.24.2 (2018-03-10)

LLVM: 5.0.1
Default target: x86_64-apple-macosx
ddrscott picture ddrscott on 6 Apr 2018

via git bisect, 074d61c4845f22939b29a8024129f892e609d0f0 is the commit which introduces this problem.
I added the following spec to compiler/codegen/if_spec.cr to test for the condition.

  it "doesn't detect type in else condition (bug)" do
    codegen(%(
      v = nil : String
      if v.nil?
      else
        sizeof(typeof(v))
      end
      ))
  end

I'm still not familiar with why that code was added, but I'm still poking around.

ddrscott picture ddrscott on 7 Apr 2018

I forked and branched to show the test:
https://github.com/ddrscott/crystal/tree/ISSUE_5717

ddrscott picture ddrscott on 7 Apr 2018

So the problem is that sizeof should raise an error when called for an empty type, but sometimes this can happen on legitimate code (in a branch that is never executed). How can it be solved?

  • return 0 instead of raising an error? Will solve the issues but can sometimes hide an error.
  • return something that will raise at runtime (no idea on how to do it).
konovod picture konovod on 8 Apr 2018

Is it possible to:

  • detect the unreachable branch and prune it?
  • keep the type with the nil value. So in this case I'd expect 8 to be returned.
ddrscott picture ddrscott on 9 Apr 2018
Was this page helpful?
0 / 5 - 0 ratings

Related issues

asterite picture asterite  路  3Comments
will picture will  路  3Comments
oprypin picture oprypin  路  3Comments
costajob picture costajob  路  3Comments
asterite picture asterite  路  3Comments