Add disambiguities

Author: MilesCranmer

src/disambiguities.jl

@@ -23,6 +23,9 @@ Base.:*(l::Number, r::AbstractDimensions) = error("Please use an `UnionAbstractQ
 Base.:/(l::AbstractDimensions, r::Number) = error("Please use an `UnionAbstractQuantity` for division. You used division on types: $(typeof(l)) and $(typeof(r)).")
 Base.:/(l::Number, r::AbstractDimensions) = error("Please use an `UnionAbstractQuantity` for division. You used division on types: $(typeof(l)) and $(typeof(r)).")
 
+SymbolicDimensionsSingleton{R}(::D) where {R,D<:AbstractDimensions} = error("SymbolicDimensionsSingleton must be constructed explicitly rather than converted to.")
+SymbolicDimensionsSingleton{R}(::Type{R2}) where {R,R2} = error("SymbolicDimensionsSingleton requires a dimension to be specified.")
+
 # Promotion ambiguities
 function Base.promote_rule(::Type{F}, ::Type{Bool}) where {F<:FixedRational}
     return F

src/symbolic_dimensions.jl

@@ -53,8 +53,6 @@ be used for constructing symbolic units and constants without needing to allocat
 """
 struct SymbolicDimensionsSingleton{R} <: AbstractSymbolicDimensions{R}
     dim::INDEX_TYPE
-
-    SymbolicDimensionsSingleton(dim::INDEX_TYPE, ::Type{_R}) where {_R} = new{_R}(dim)
 end
 
 # Access:
@@ -93,7 +91,7 @@ end
 function SymbolicDimensionsSingleton{R}(s::Symbol) where {R}
     i = get(ALL_MAPPING, s, INDEX_TYPE(0))
     iszero(i) && error("$s is not available as a symbol in `SymbolicDimensionsSingleton`. Symbols available: $(ALL_SYMBOLS).")
-    return SymbolicDimensionsSingleton(i, R)
+    return SymbolicDimensionsSingleton{R}(i)
 end
 
 # Traits:
@@ -199,7 +197,7 @@ a function equivalent to `q -> uconvert(qout, q)`.
 uconvert(qout::UnionAbstractQuantity{<:Any,<:AbstractSymbolicDimensions}) = Base.Fix1(uconvert, qout)
 
 Base.copy(d::SymbolicDimensions) = SymbolicDimensions(copy(nzdims(d)), copy(nzvals(d)))
-Base.copy(d::SymbolicDimensionsSingleton) = SymbolicDimensionsSingleton(getfield(d, :dim), eltype(d))
+Base.copy(d::SymbolicDimensionsSingleton) = constructorof(d)(getfield(d, :dim))
 
 function Base.:(==)(l::AbstractSymbolicDimensions, r::AbstractSymbolicDimensions)
     nzdims_l = nzdims(l)

test/unittests.jl

@@ -824,12 +824,15 @@ end
         @test promote_rule(typeof(π), typeof(x)) == promote_type(Rational{Int32}, typeof(π))
     end
 
-    @testset "Weakref" begin
+    @testset "Unimplemented on purpose" begin
         x = 1.0u"m"
         s = "test"
         y = WeakRef(s)
         @test_throws ErrorException x == y
         @test_throws ErrorException y == x
+
+        @test_throws ErrorException DynamicQuantities.SymbolicDimensionsSingleton{Int}(Dimensions())
+        @test_throws ErrorException DynamicQuantities.SymbolicDimensionsSingleton{Int}(UInt32)
     end
 
     @testset "Arrays" begin