Invalid memory access in Array#push

[vlazar]

Array#push fails

ary=[] of UInt32
p! ary.push(3)

Output

Invalid memory access (signal 11) at address 0x0
[0x55d1aecf1b06] *CallStack::print_backtrace:Int32 +118
[0x55d1aece4981] __crystal_sigfault_handler +209
[0x7f42fe0ad930] ???
[0x0] ???

Array#<< works

ary=[] of UInt32
p! ary << 3 # => [3]

Note however that locally I have this error instead for Array#push:

ary=[] of UInt32
p! ary.push(3) # => Program received and didn't handle signal ILL (4)

Crystal 0.32.0 on MacOS

$ crystal --version
Crystal 0.32.0 (2019-12-12)

LLVM: 9.0.0
Default target: x86_64-apple-macosx

The behavior changed many times in previous versions of Crystal. Although I'm not sure if I can trust playground.

In Crystal 0.24.2 both Array#push and Array#<< gives no overload matches error.

Since Crystal 0.25.0 Array#push is broken and Array#<< works.

Since Crystal 0.27.0 Array#push gives ambiguous call, implicit cast of 3 matches all of UInt32 and Array#<< works.

SInce Crystal 0.29.0 Array#push gives Program received and didn't handle signal SYS (31) and Array#<< works.

SInce Crystal 0.31.0 Array#push gives Invalid memory access and Array#<< works.

[vlazar]

Seem to be related to #6074 #6618 and #7747

[vlazar]

Only Int32 is working with Array#push

# ary=[] of UInt64
# p! ary.push(3) # => Program received and didn't handle signal ILL (4)

# ary=[] of UInt32
# p! ary.push(3) # => Program received and didn't handle signal ILL (4)

# ary=[] of UInt16
# p! ary.push(3) # => Program received and didn't handle signal ILL (4)

# ary=[] of UInt8
# p! ary.push(3) # => Program received and didn't handle signal ILL (4)

# ary=[] of Int64
# p! ary.push(3) # => Program received and didn't handle signal ILL (4)

ary=[] of Int32
p! ary.push(3) # => [3]

# ary=[] of Int16
# p! ary.push(3) # => Program received and didn't handle signal ILL (4)

# ary=[] of Int8
# p! ary.push(3) # => Program received and didn't handle signal ILL (4)

Crystal 0.32.0 on MacOS

$ crystal --version
Crystal 0.32.0 (2019-12-12)

LLVM: 9.0.0
Default target: x86_64-apple-macosx

[asterite]

It seems to be a bug with autocasting. It works fine if you do push(3_u32).

[vlazar]

BTW, is that by design that Array#push has overloads for single value and multiple values, but Array#<< works only for single value?

Should't there be this variant too?

class Array(T)
  def <<(*values : T)
   push(*values)
  end
end

Then Array#<< will fail as Array#push in this issue.

[asterite]

@vlazar the syntax doesn't allow calling << with multiple arguments, unless you do a.<<(1, 2, 3), but for that you can use push.

[vlazar]

@asterite Thanks. Yeah, that was my though. I just wanted to be sure it was not forgotten, but deliberately not added in the first place.

[RX14]

I'm certain this is #8217. If it is, close for dupe?

[asterite]

Duplicate of #8217