Implement is_convertible_from_type for concepts

nelua/types.lua

@@ -15,6 +15,7 @@ local metamagic = require 'nelua.utils.metamagic'
 local bn = require 'nelua.utils.bn'
 local except = require 'nelua.utils.except'
 local shaper = require 'nelua.utils.shaper'
+local Attr = require 'nelua.attr'
 local config = require 'nelua.configer'.get()
 
 local types = {}
@@ -2134,6 +2135,12 @@ function ConceptType:get_convertible_from_attr(attr, _, argattrs)
   return type, err
 end
 
+-- Checks if this type is convertible from another type.
+function ConceptType:is_convertible_from_type(type, explicit)
+  local attr = Attr{type=type}
+  return self:get_convertible_from_attr(attr, explicit, {attr})
+end
+
 function types.make_overload_concept(context, syms, ...)
   if traits.is_symbol(syms) or traits.is_type(syms) then
     syms = table.pack(syms, ...)

spec/03-typechecker_spec.lua

@@ -1487,6 +1487,7 @@ it("concepts", function()
     local an_integral = #[concept(function(x)
       return x.type.is_integral
     end)]#
+    ## static_assert(an_integral.value:is_convertible_from_type(primtypes.integer))
     local an_integer_array = #[concept(function(x)
       return x.type:is_array_of(primtypes.integer)
     end)]#