Fix type inference on earlier Julia

Author: MilesCranmer

src/BaseType.jl

@@ -20,9 +20,9 @@ For example,
 ]
 ```
 """
-function base_numeric_type(::Type{T}) where {T}
+@generated function base_numeric_type(::Type{T}) where {T}
     params = T isa UnionAll ? T.body.parameters : T.parameters
-    return isempty(params) ? T : first(params)
+    return isempty(params) ? :($T) : :($(first(params)))
 end
 base_numeric_type(x) = base_numeric_type(typeof(x))
 

test/unittests.jl

@@ -25,12 +25,8 @@ expected_type_pairs = [
 for (x, y) in expected_type_pairs
     @eval @test base_numeric_type($x) == $y
     # Make sure compiler can inline it:
-    if VERSION >= v"1.10"
-        @eval @inferred $y base_numeric_type($x)
-    end
+    @eval @inferred $y base_numeric_type($x)
 end
 
 @test base_numeric_type(1.5DynamicQuantities.u"km/s") == base_numeric_type(typeof(1.5DynamicQuantities.u"km/s"))
-if VERSION >= v"1.10"
-    @inferred base_numeric_type(1.5DynamicQuantities.u"km/s")
-end
+@inferred base_numeric_type(1.5DynamicQuantities.u"km/s")