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Fix overflow in complex // #60130

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Fix overflow in complex // #60130

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303a070
Fix overflow in complex //
nhz2 Nov 14, 2025
48de111
Improve integer case
nhz2 Nov 14, 2025
6d87a3e
Remove TODO comment
nhz2 Nov 14, 2025
8549732
remove extra newline
nhz2 Nov 14, 2025
cfaab24
Fix `//(x::Number, y::Complex)`
nhz2 Nov 15, 2025
8bcaa34
add suggestion
nhz2 Nov 15, 2025
aff40d0
Move dispatch to a helper function
nhz2 Nov 16, 2025
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20 changes: 20 additions & 0 deletions base/rational.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -105,8 +105,28 @@ function //(x::Rational, y::Rational)
end

//(x::Complex, y::Real) = complex(real(x)//y, imag(x)//y)

# TODO Unclear if this method should be defined. It seems to conflict with the docstring that states that "The arguments must be subtypes of Integer, Rational, or composites thereof."
//(x::Number, y::Complex) = x*conj(y)//abs2(y)

function //(x::Union{Integer, Rational, Complex{<:Union{Rational, Integer}}}, y::Complex{<:Union{Rational, Integer}})
x/y
end
function //(x::Integer, y::Complex{<:Integer})
a, c, d = promote(x, reim(y)...)
c_r, d_r = divgcd(c, d)
abs2y_r = checked_add(checked_mul(c, c_r), checked_mul(d, d_r))
complex(checked_mul(a, c_r), checked_neg(checked_mul(a, d_r)))//abs2y_r
end
function //(x::Complex{<:Integer}, y::Complex{<:Integer})
a, b, c, d = promote(reim(x)..., reim(y)...)
c_r, d_r = divgcd(c, d)
abs2y_r = checked_add(checked_mul(c, c_r), checked_mul(d, d_r))
complex(
checked_add(checked_mul(a, c_r), checked_mul(b, d_r)),
checked_add(checked_mul(b, c_r), checked_neg(checked_mul(a, d_r)))
)//abs2y_r
end

//(X::AbstractArray, y::Number) = X .// y

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7 changes: 7 additions & 0 deletions test/rational.jl
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Expand Up @@ -215,9 +215,16 @@ end
@test_throws DivideError (0//1) / complex(0, 0)
@test_throws DivideError (1//1) / complex(0, 0)
@test_throws DivideError (1//0) / complex(0, 0)
@test_throws DivideError 1 // complex(0, 0)
@test_throws DivideError 0 // complex(0, 0)
@test_throws DivideError complex(1) // complex(0, 0)
@test_throws DivideError complex(0) // complex(0, 0)

# 1//200 - 1//200*im cannot be represented as Complex{Rational{Int8}}
@test_throws OverflowError (Int8(1)//Int8(1)) / (Int8(100) + Int8(100)im)
@test_throws OverflowError (Int8(1)//Int8(1)) // (Int8(100) + Int8(100)im)
@test_throws OverflowError Int8(1) // (Int8(100) + Int8(100)im)
@test_throws OverflowError complex(Int8(1)) // (Int8(100) + Int8(100)im)

@test Complex(rand_int, 0) == Rational(rand_int)
@test Rational(rand_int) == Complex(rand_int, 0)
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