Fix dot product between Rational{Int} and Rational{BigInt} (#322)

* Add promotion on gcd and lcm for BigInt

* Fix dot product between Rational{Int} and Rational{BigInt}

* Fix

* Fix format

src/implementations/BigInt.jl

@@ -182,7 +182,14 @@ _scaling_to_bigint(x) = _scaling_to(BigInt, x)
 
 function operate_to!(
     output::BigInt,
-    op::Union{typeof(+),typeof(-),typeof(*)},
+    op::Union{
+        typeof(+),
+        typeof(-),
+        typeof(*),
+        typeof(div),
+        typeof(gcd),
+        typeof(lcm),
+    },
     args::Vararg{Scaling,N},
 ) where {N}
     return operate_to!(output, op, _scaling_to_bigint.(args)...)

src/implementations/Rational.jl

@@ -178,7 +178,7 @@ function buffer_for(
     ::Type{Rational{T}},
 ) where {S,T}
     U = promote_operation(gcd, S, T)
-    return zero(Rational{S}), zero(Rational{T}), zero(U)
+    return zero(Rational{U}), zero(Rational{U}), zero(U)
 end
 
 function buffered_operate_to!(

test/interface.jl

@@ -123,6 +123,20 @@ end
                 @test a !== b
             end
         end
+        @testset "dot" for U in (Int, BigInt, Rational{Int}, Rational{BigInt})
+            y = U(5)
+            a = LinearAlgebra.dot(x, y)
+            b = MA.operate(LinearAlgebra.dot, [x], [y])
+            @test a == b
+            if MA.mutability(
+                promote_type(T, U),
+                LinearAlgebra.dot,
+                Vector{T},
+                Vector{U},
+            ) == MA.IsMutable()
+                @test a !== b
+            end
+        end
     end
 end