File 1128-beam_validator-Eliminate-type-mismatch.patch of Package erlang

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File 1128-beam_validator-Eliminate-type-mismatch.patch of Package erlang (Revision 2c13fe5010c2373357f7eed932e78181)

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From 28fce1f8016a8bf52ca6a109aa471700f17e772b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Mon, 14 Nov 2022 09:01:57 +0100
Subject: [PATCH] beam_validator: Eliminate type mismatch

When compiling the following code:

f1({X}) when X; (X orelse false) ->
        (X orelse {}),
        [
            {X}#{
                f2() orelse X => []
            }
         || _ <- []
        ].

f2() ->
        0.

the `beam_validator` pass rejects it:

call_only:1: function f1/1+27:
      Internal consistency check failed - please report this bug.
      Instruction: {call_only,3,{f,16}}
      Error:       {bad_arg_type,
                       {x,1},
                       {t_tuple,1,true,#{1 => {t_atom,[false,true]}}},
                       {t_union,none,none,none,
                           [{{1,{t_atom,[false]}},
                             {t_tuple,1,true,#{1 => {t_atom,[false]}}}},
                            {{1,{t_atom,[true]}},
                             {t_tuple,1,true,#{1 => {t_atom,[true]}}}}],
                           none}}:

What happens here is that when types are updated in different ways,
the result will be different. That is not supposed to happen; there
should be one canonical type representation regardless how it's
reached.

This commit resolves the bug for this particular example, but a more
general solution might be needed.

Closes #6458
---
 lib/compiler/src/beam_validator.erl   | 23 ++++++++++++++++++++---
 lib/compiler/test/beam_type_SUITE.erl | 17 +++++++++++++++++
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index f98bbe894f..a29ba664d7 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -2547,13 +2547,30 @@ update_container_type(Type, Ref, #vst{current=#st{vs=Vs}}=Vst) ->
     case Vs of
         #{ Ref := #value{op={bif,element},
                          args=[{integer,Index},Tuple]} } when Index >= 1 ->
-            Es = beam_types:set_tuple_element(Index, Type, #{}),
-            TupleType = #t_tuple{size=Index,elements=Es},
-            update_type(fun meet/2, TupleType, Tuple, Vst);
+            case {Index,Type} of
+                {1,#t_atom{elements=[_,_|_]}} ->
+                    %% The first element is one atom out of a set of
+                    %% at least two atoms. We must take care to
+                    %% construct an atom set.
+                    update_type(fun meet_tuple_set/2, Type, Tuple, Vst);
+                {_,_} ->
+                    Es = beam_types:set_tuple_element(Index, Type, #{}),
+                    TupleType = #t_tuple{size=Index,elements=Es},
+                    update_type(fun meet/2, TupleType, Tuple, Vst)
+            end;
         #{} ->
             Vst
     end.
 
+meet_tuple_set(Type, #t_atom{elements=Atoms}) ->
+    %% Try to create a tuple set out of the known atoms for the first element.
+    #t_tuple{size=Size,exact=Exact} = normalize(meet(Type, #t_tuple{})),
+    Tuples = [#t_tuple{size=Size,exact=Exact,
+                       elements=#{1 => #t_atom{elements=[A]}}} ||
+                 A <- Atoms],
+    TupleSet = foldl(fun join/2, hd(Tuples), tl(Tuples)),
+    meet(Type, TupleSet).
+
 update_eq_types(LHS, RHS, Vst0) ->
     LType = get_term_type(LHS, Vst0),
     RType = get_term_type(RHS, Vst0),
diff --git a/lib/compiler/test/beam_type_SUITE.erl b/lib/compiler/test/beam_type_SUITE.erl
index 8bdce54543..9bc680120d 100644
--- a/lib/compiler/test/beam_type_SUITE.erl
+++ b/lib/compiler/test/beam_type_SUITE.erl
@@ -622,6 +622,11 @@ tuple(_Config) ->
     {0,0,-1} = decrement_element(3, Counters10),
     {'EXIT',{badarg,_}} = catch decrement_element(4, Counters10),
 
+    [] = gh_6458(id({true})),
+    {'EXIT',{function_clause,_}} = catch gh_6458(id({false})),
+    {'EXIT',{function_clause,_}} = catch gh_6458(id({42})),
+    {'EXIT',{function_clause,_}} = catch gh_6458(id(a)),
+
     ok.
 
 do_tuple() ->
@@ -641,6 +646,18 @@ decrement_element(Pos, Cs) ->
     Ns = element(Pos, Cs),
     setelement(Pos, Cs, Ns - 1).
 
+gh_6458({X}) when X; (X orelse false) ->
+    (X orelse {}),
+    [
+     {X}#{
+          gh_6458() orelse X => []
+         }
+     || _ <- []
+    ].
+
+gh_6458() ->
+    true.
+
 -record(x, {a}).
 
 record_float(_Config) ->
-- 
2.35.3

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File 1128-beam_validator-Eliminate-type-mismatch.patch of Package erlang (Revision 2c13fe5010c2373357f7eed932e78181)

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