attempt to fix vararg type caching when there are constraints on vara…

…rg length
JuliaLang · Apr 18, 2018 · 9d620dc · 9d620dc
1 parent 6eb27fd
commit 9d620dc
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Showing 2 changed files with 16 additions and 5 deletions.
diff --git a/base/compiler/inferenceresult.jl b/base/compiler/inferenceresult.jl
@@ -36,16 +36,19 @@ function get_argtypes(result::InferenceResult)
             if nargs > laty
                 va = atypes[laty]
                 if isvarargtype(va)
-                    # assumes that we should never see Vararg{T, x}, where x is a constant (should be guaranteed by construction)
-                    va = rewrap_unionall(va, linfo.specTypes)
-                    vararg_type_vec = Any[va]
-                    vararg_type = Tuple{va}
+                    new_va = rewrap_unionall(unconstrain_vararg_length(va), linfo.specTypes)
+                    vararg_type_vec = Any[new_va]
+                    vararg_type = Tuple{new_va}
                 else
                     vararg_type_vec = Any[]
                     vararg_type = Tuple{}
                 end
             else
-                vararg_type_vec = Any[rewrap_unionall(p, linfo.specTypes) for p in atypes[nargs:laty]]
+                vararg_type_vec = Any[]
+                for p in atypes[nargs:laty]
+                    p = isvarargtype(p) ? unconstrain_vararg_length(p) : p
+                    push!(vararg_type_vec, rewrap_unionall(p, linfo.specTypes))
+                end
                 vararg_type = tuple_tfunc(Tuple{vararg_type_vec...})
                 for i in 1:length(vararg_type_vec)
                     atyp = vararg_type_vec[i]

diff --git a/base/essentials.jl b/base/essentials.jl
@@ -213,6 +213,14 @@ function unwrapva(@nospecialize(t))
     isvarargtype(t2) ? rewrap_unionall(t2.parameters[1],t) : t
 end
 
+function unconstrain_vararg_length(@nospecialize(va))
+    # construct a new Vararg type where its length is unconstrained,
+    # but its element type still captures any dependencies the input
+    # element type may have had on the input length
+    T = unwrap_unionall(va).parameters[1]
+    return rewrap_unionall(Vararg{T}, va)
+end
+
 typename(a) = error("typename does not apply to this type")
 typename(a::DataType) = a.name
 function typename(a::Union)