fix a transitivity issue in specificity, from #26915 (#27042)

JuliaLang · May 10, 2018 · 5fb465f · 5fb465f
1 parent fb1c21c
commit 5fb465f
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diff --git a/src/subtype.c b/src/subtype.c
@@ -2377,7 +2377,7 @@ static int tuple_morespecific(jl_datatype_t *cdt, jl_datatype_t *pdt, int invari
         int cms = type_morespecific_(ce, pe, invariant, env);
         int eqv = !cms && eq_msp(ce, pe, env);
 
-        if (!cms && !eqv) {
+        if (!cms && !eqv && !sub_msp(ce, pe, env)) {
             /*
               A bound vararg tuple can be more specific despite disjoint elements in order to
               preserve transitivity. For example in

diff --git a/test/specificity.jl b/test/specificity.jl
@@ -193,3 +193,12 @@ let A = Tuple{Array{T,N}, Vararg{Int,N}} where {T,N},
     @test args_morespecific(B, C)
     @test args_morespecific(A, C)
 end
+
+# transitivity issue found in #26915
+let A = Tuple{Vector, AbstractVector},
+    B = Tuple{AbstractVecOrMat{T}, AbstractVector{T}} where T,
+    C = Tuple{AbstractVecOrMat{T}, AbstractVecOrMat{T}} where T
+    @test args_morespecific(A, B)
+    @test args_morespecific(B, C)
+    @test args_morespecific(A, C)
+end