Fix broadcasting

src/methods.jl

@@ -3,6 +3,8 @@
 # Unwrap to the storage value. The macro installs a `storagetypeof(::Type{T}) = <storage_type>` constant-returning method per emulated type, so this folds to a single `reinterpret`. On Julia >= 1.13, `@emulate` additionally installs a per-type, `range`-annotated `getindex` (see `emulate.jl`) that is strictly more specific and wins dispatch; this abstract method then only serves as the fallback on older Julia (LLVM < 19, where the `range` attribute is unavailable).
 Base.getindex(x::EmulatedInteger) = reinterpret(x |> typeof |> storagetypeof, x)
 
+Base.broadcastable(x::EmulatedInteger) = Ref(x)
+
 # Value form returns a wider value (the unwrapped storage int); type form returns the storage type. Both routed through the per-type `storagetypeof` trait.
 Base.widen(x::EmulatedInteger) = x[]
 Base.widen(::Type{T}) where T<:EmulatedInteger = storagetypeof(T)

test/broadcasting.jl

@@ -0,0 +1,35 @@
+@testset "scalar broadcasting" begin
+    @emulate Int3 UInt3 Int3_128 UInt3_128
+
+    @test Int3(2) * Int3[2] == Int3[-4]
+    @test UInt3(3) * UInt3[3] == UInt3[1]
+
+    for Element in (Int3, UInt3, Int3_128, UInt3_128)
+        for scalar in (Element(2), typemin(Element), typemax(Element))
+            vector = Element[2, 3]
+            expected = map(value -> scalar * value, vector)
+            @test Base.broadcastable(scalar)[] === scalar
+            @test identity.(scalar) === scalar
+            @test scalar .* scalar === scalar * scalar
+            @test scalar * vector == expected
+            @test vector * scalar == expected
+            @test scalar .* vector == expected
+            @test vector .* scalar == expected
+            @test eltype(scalar * vector) === Element
+            @test eltype(vector * scalar) === Element
+            @test eltype(scalar .* vector) === Element
+            @test scalar .+ vector == map(value -> scalar + value, vector)
+            @test scalar .* (vector .+ scalar) == map(value -> scalar * (value + scalar), vector)
+            destination = similar(vector)
+            destination .= scalar .* vector
+            @test destination == expected
+            matrix = reshape(vector, 1, 2)
+            @test scalar * matrix == reshape(expected, 1, 2)
+            @test matrix * scalar == reshape(expected, 1, 2)
+            @test scalar * fill(Element(2)) == fill(scalar * Element(2))
+            @test eltype(scalar * fill(Element(2))) === Element
+            @test isempty(scalar * Element[])
+            @test eltype(scalar * Element[]) === Element
+        end
+    end
+end

test/runtests.jl

@@ -17,6 +17,7 @@ values(x) = x |> fieldvalues |> collect
 
 include("comparisons.jl")
 include("sums.jl")
+include("broadcasting.jl")
 
 # ============================================================================
 # Static analysis