more precise t-function for is

JuliaLang · May 6, 2016 · 1782c49 · 1782c49
1 parent e0e93fc
commit 1782c49
Showing 1 changed file with 11 additions and 1 deletion.
diff --git a/base/inference.jl b/base/inference.jl
@@ -275,7 +275,17 @@ add_tfunc(Core.Intrinsics.select_value, 3, 3,
  tmerge(x, y)
  end)
 add_tfunc(is, 2, 2,
- (x::ANY, y::ANY)->(isa(x,Const) && isa(y,Const) ? Const(x.val===y.val) : Bool))
+ function (x::ANY, y::ANY)
+ if isa(x,Const) && isa(y,Const)
+ return Const(x.val===y.val)
+ elseif isType(x) && isType(y) && isleaftype(x) && isleaftype(y)
+ return Const(x.parameters[1]===y.parameters[1])
+ elseif typeintersect(widenconst(x), widenconst(y)) === Bottom
+ return Const(false)
+ else
+ return Bool
+ end
+ end)
 add_tfunc(isdefined, 1, IInf, (args...)->Bool)
 add_tfunc(Core.sizeof, 1, 1, x->Int)
 add_tfunc(nfields, 1, 1, x->(isa(x,Const) ? Const(nfields(x.val)) :