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Merge pull request #16249 from JuliaLang/teh/morespecific_vararg
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Fix specificity with bound varargs
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@timholy
timholy authored Jun 24, 2016
2 parents 26fec34 + 9614c40 commit beab3b6
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Showing 3 changed files with 114 additions and 35 deletions.
102 changes: 102 additions & 0 deletions src/jltypes.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2777,6 +2777,21 @@ static int type_eqv_with_ANY(jl_value_t *a, jl_value_t *b)

static int jl_type_morespecific_(jl_value_t *a, jl_value_t *b, int invariant);

jl_datatype_t *jl_fix_vararg_bound(jl_datatype_t *tt, int nfix)
{
assert(jl_is_va_tuple(tt));
assert(nfix >= 0);
jl_svec_t *tp = tt->parameters;
size_t ntp = jl_svec_len(tp);
jl_value_t *env[2] = {NULL, NULL};
JL_GC_PUSH2(&env[0], &env[1]);
env[0] = jl_tparam1(jl_tparam(tt, ntp-1));
env[1] = jl_box_long(nfix);
jl_datatype_t *ret = (jl_datatype_t*)jl_instantiate_type_with((jl_value_t*)tt, env, 2);
JL_GC_POP();
return ret;
}

static int jl_tuple_morespecific(jl_datatype_t *cdt, jl_datatype_t *pdt, int invariant)
{
size_t clenr = jl_nparams(cdt);
Expand Down Expand Up @@ -2999,6 +3014,93 @@ JL_DLLEXPORT int jl_type_morespecific(jl_value_t *a, jl_value_t *b)
return jl_type_morespecific_(a, b, 0);
}

int jl_args_morespecific_(jl_value_t *a, jl_value_t *b)
{
int msp = jl_type_morespecific(a,b);
int btv = jl_has_typevars(b);
if (btv) {
if (jl_type_match_morespecific(a,b) == (jl_value_t*)jl_false) {
if (jl_has_typevars(a))
return 0;
return msp;
}
if (jl_has_typevars(a)) {
type_match_invariance_mask = 0;
//int result = jl_type_match_morespecific(b,a) == (jl_value_t*)jl_false);
// this rule seems to work better:
int result = jl_type_match(b,a) == (jl_value_t*)jl_false;
type_match_invariance_mask = 1;
if (result)
return 1;
}
int nmsp = jl_type_morespecific(b,a);
if (nmsp == msp)
return 0;
}
if (jl_has_typevars((jl_value_t*)a)) {
int nmsp = jl_type_morespecific(b,a);
if (nmsp && msp)
return 1;
if (!btv && jl_types_equal(a,b))
return 1;
if (jl_type_match_morespecific(b,a) != (jl_value_t*)jl_false)
return 0;
}
return msp;
}

// Called when a is a bound-vararg and b is not a vararg. Sets the
// vararg length in a to match b, as long as this makes some earlier
// argument more specific.
int jl_args_morespecific_fix1(jl_value_t *a, jl_value_t *b, int swap)
{
jl_datatype_t *tta = (jl_datatype_t*)a;
jl_datatype_t *ttb = (jl_datatype_t*)b;
size_t n = jl_nparams(tta);
jl_datatype_t *newtta = jl_fix_vararg_bound(tta, jl_nparams(ttb)-n+1);
int changed = 0;
for (size_t i = 0; i < n-1; i++) {
if (jl_tparam(tta, i) != jl_tparam(newtta, i)) {
changed = 1;
break;
}
}
if (changed) {
JL_GC_PUSH1(&newtta);
int ret;
if (swap)
ret = jl_args_morespecific_(b, (jl_value_t*)newtta);
else
ret = jl_args_morespecific_((jl_value_t*)newtta, b);
JL_GC_POP();
return ret;
}
if (swap)
return jl_args_morespecific_(b, a);
return jl_args_morespecific_(a, b);
}

JL_DLLEXPORT int jl_args_morespecific(jl_value_t *a, jl_value_t *b)
{
if (jl_is_tuple_type(a) && jl_is_tuple_type(b)) {
jl_datatype_t *tta = (jl_datatype_t*)a;
jl_datatype_t *ttb = (jl_datatype_t*)b;
size_t alenf, blenf;
jl_vararg_kind_t akind, bkind;
jl_tuple_lenkind_t alenkind, blenkind;
alenf = tuple_vararg_params(tta->parameters, NULL, &akind, &alenkind);
blenf = tuple_vararg_params(ttb->parameters, NULL, &bkind, &blenkind);
// When one is JL_VARARG_BOUND and the other has fixed length,
// allow the argument length to fix the tvar
if (akind == JL_VARARG_BOUND && blenkind == JL_TUPLE_FIXED && blenf >= alenf) {
return jl_args_morespecific_fix1(a, b, 0);
}
if (bkind == JL_VARARG_BOUND && alenkind == JL_TUPLE_FIXED && alenf >= blenf) {
return jl_args_morespecific_fix1(b, a, 1);
}
}
return jl_args_morespecific_(a, b);
}

// ----------------------------------------------------------------------------

Expand Down
35 changes: 0 additions & 35 deletions src/typemap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1008,41 +1008,6 @@ jl_typemap_entry_t *jl_typemap_insert(union jl_typemap_t *cache, jl_value_t *par
return newrec;
}

JL_DLLEXPORT int jl_args_morespecific(jl_value_t *a, jl_value_t *b)
{
int msp = jl_type_morespecific(a,b);
int btv = jl_has_typevars(b);
if (btv) {
if (jl_type_match_morespecific(a,b) == (jl_value_t*)jl_false) {
if (jl_has_typevars(a))
return 0;
return msp;
}
if (jl_has_typevars(a)) {
type_match_invariance_mask = 0;
//int result = jl_type_match_morespecific(b,a) == (jl_value_t*)jl_false);
// this rule seems to work better:
int result = jl_type_match(b,a) == (jl_value_t*)jl_false;
type_match_invariance_mask = 1;
if (result)
return 1;
}
int nmsp = jl_type_morespecific(b,a);
if (nmsp == msp)
return 0;
}
if (jl_has_typevars((jl_value_t*)a)) {
int nmsp = jl_type_morespecific(b,a);
if (nmsp && msp)
return 1;
if (!btv && jl_types_equal(a,b))
return 1;
if (jl_type_match_morespecific(b,a) != (jl_value_t*)jl_false)
return 0;
}
return msp;
}

static int has_unions(jl_tupletype_t *type)
{
int i;
Expand Down
12 changes: 12 additions & 0 deletions test/core.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -206,6 +206,18 @@ let T = TypeVar(:T, Tuple{Vararg{RangeIndex}}, true)
@test args_morespecific(t2, t1)
end

let T = TypeVar(:T, Any, true), N = TypeVar(:N, Any, true)
a = Tuple{Array{T,N}, Vararg{Int,N}}
b = Tuple{Array,Int}
@test args_morespecific(a, b)
@test !args_morespecific(b, a)
a = Tuple{Array, Vararg{Int,N}}
@test !args_morespecific(a, b)
@test args_morespecific(b, a)
end

# with bound varargs

# issue #11840
typealias TT11840{T} Tuple{T,T}
f11840(::Type) = "Type"
Expand Down

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