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Add examples of list comprehension generators being none() #434

Merged
merged 5 commits into from
Aug 22, 2022
Merged

Add examples of list comprehension generators being none() #434

merged 5 commits into from
Aug 22, 2022

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erszcz
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@erszcz erszcz commented Aug 11, 2022 •
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This is a set of examples for #433 found based on the error message for typechecker:has_overlapping_keys/2 and tracing execution.

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erszcz commented Aug 11, 2022 •
edited
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A somewhat bigger example is:

-type type() :: erl_parse:abstract_type().

-spec f(type()) -> [x].
f({type, _, map, Assocs}) ->
    [ x || As1 <- Assocs, As2 <- Assocs, As1 /= As2 ].

The call to GLB which leads to the type of the generator being inferred as none() is

Gradualizer/src/typechecker.erl

Lines 4286 to 4310 in f647ae7

add_type_pat(Pat, ?type(union, UnionTys) = UnionTy, Env) ->
{PatTys, UBounds, Envs, Css} =
lists:foldr(fun (Ty, {PatTysAcc, UBoundsAcc, EnvAcc, CsAcc} = Acc) ->
%% Ty is normalized, since UnionTy is normalized
try add_type_pat(Pat, Ty, Env) of
{PatTy, UBound, NewEnv, Cs} ->
{[PatTy|PatTysAcc],
[UBound|UBoundsAcc],
[NewEnv|EnvAcc],
[Cs|CsAcc]}
catch _TypeError ->
Acc
end
end,
{[], [], [], []},
UnionTys),
case PatTys of
[] ->
%% Pattern doesn't match any type in the union
Anno = element(2, Pat),
throw(type_error(pattern, Anno, Pat, UnionTy));
_SomeTysMatched ->
%% TODO: The constraints should be merged with *or* semantics
%% and var binds with intersection
{Ty, Cs} = glb(PatTys, Env),

The corresponding trace is:

{trace,<0.86.0>,call,
    {typechecker,glb_ty,
        [{type,0,tuple,
             [{atom,0,type},
              {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
              {atom,0,map},
              {type,0,list,
                  [{user_type,
                       [{file,"erl_parse.erl"},{location,0}],
                       af_assoc_type,[]}]}]},
         {type,0,tuple,
             [{atom,0,type},
              {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
              {atom,0,map},
              {atom,0,any}]},
         #{{{type,0,tuple,
                [{atom,0,type},
                 {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
                 {atom,0,map},
                 {type,0,list,
                     [{user_type,
                          [{file,"erl_parse.erl"},{location,0}],
                          af_assoc_type,[]}]}]},
            {type,0,tuple,
                [{atom,0,type},
                 {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
                 {atom,0,map},
                 {atom,0,any}]}} =>
               0},
         {env,
             #{{f,1} =>
                   [{type,
                        {7,8},
                        bounded_fun,
                        [{type,
                             {7,8},
                             'fun',
                             [{type,{7,8},product,[{user_type,{7,9},type,[]}]},
                              {type,{7,20},list,[{atom,{7,21},x}]}]},
                         []]}]},
             #{},#{},
             #{module => lc,records => #{},
               types =>
                   #{{type,0} =>
                         {[],
                          {remote_type,0,
                              [{atom,{5,17},erl_parse},
                               {atom,{5,27},abstract_type},
                               []]}}}},
             false,false,true,
             [{clauses_controls,true}],
             30,
             [{type,
                  {7,8},
                  bounded_fun,
                  [{type,
                       {7,8},
                       'fun',
                       [{type,{7,8},product,[{user_type,{7,9},type,[]}]},
                        {type,{7,20},list,[{atom,{7,21},x}]}]},
                   []]}]}]}}
{trace,<0.86.0>,call,
    {typechecker,glb_ty,
        [{atom,0,type},
         {atom,0,type},
         #{{{atom,0,type},{atom,0,type}} => 0,
           {{type,0,tuple,
                [{atom,0,type},
                 {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
                 {atom,0,map},
                 {type,0,list,
                     [{user_type,
                          [{file,"erl_parse.erl"},{location,0}],
                          af_assoc_type,[]}]}]},
            {type,0,tuple,
                [{atom,0,type},
                 {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
                 {atom,0,map},
                 {atom,0,any}]}} =>
               0},
         {env,
             #{{f,1} =>
                   [{type,
                        {7,8},
                        bounded_fun,
                        [{type,
                             {7,8},
                             'fun',
                             [{type,{7,8},product,[{user_type,{7,9},type,[]}]},
                              {type,{7,20},list,[{atom,{7,21},x}]}]},
                         []]}]},
             #{},#{},
             #{module => lc,records => #{},
               types =>
                   #{{type,0} =>
                         {[],
                          {remote_type,0,
                              [{atom,{5,17},erl_parse},
                               {atom,{5,27},abstract_type},
                               []]}}}},
             false,false,true,
             [{clauses_controls,true}],
             30,
             [{type,
                  {7,8},
                  bounded_fun,
                  [{type,
                       {7,8},
                       'fun',
                       [{type,{7,8},product,[{user_type,{7,9},type,[]}]},
                        {type,{7,20},list,[{atom,{7,21},x}]}]},
                   []]}]}]}}
{trace,<0.86.0>,return_from,
       {typechecker,glb_ty,4},
       {{atom,0,type},
        {constraints,#{},#{},
                     {set,0,16,16,8,80,48,
                          {[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]},
                          {{[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],
                            []}}}}}}
{trace,<0.86.0>,return_to,{typechecker,glb,4}}
{trace,<0.86.0>,call,
    {typechecker,glb_ty,
        [{user_type,[{file,"erl_anno.erl"},{location,0}],anno,[]},
         {user_type,[{file,"erl_anno.erl"},{location,0}],anno,[]},
         #{{{type,0,tuple,
                [{atom,0,type},
                 {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
                 {atom,0,map},
                 {type,0,list,
                     [{user_type,
                          [{file,"erl_parse.erl"},{location,0}],
                          af_assoc_type,[]}]}]},
            {type,0,tuple,
                [{atom,0,type},
                 {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
                 {atom,0,map},
                 {atom,0,any}]}} =>
               0,
           {{user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
            {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]}} =>
               0},
         {env,
             #{{f,1} =>
                   [{type,
                        {7,8},
                        bounded_fun,
                        [{type,
                             {7,8},
                             'fun',
                             [{type,{7,8},product,[{user_type,{7,9},type,[]}]},
                              {type,{7,20},list,[{atom,{7,21},x}]}]},
                         []]}]},
             #{},#{},
             #{module => lc,records => #{},
               types =>
                   #{{type,0} =>
                         {[],
                          {remote_type,0,
                              [{atom,{5,17},erl_parse},
                               {atom,{5,27},abstract_type},
                               []]}}}},
             false,false,true,
             [{clauses_controls,true}],
             30,
             [{type,
                  {7,8},
                  bounded_fun,
                  [{type,
                       {7,8},
                       'fun',
                       [{type,{7,8},product,[{user_type,{7,9},type,[]}]},
                        {type,{7,20},list,[{atom,{7,21},x}]}]},
                   []]}]}]}}
{trace,<0.86.0>,return_from,
       {typechecker,glb_ty,4},
       {{user_type,[{file,"erl_anno.erl"},{location,0}],anno,[]},
        {constraints,#{},#{},
                     {set,0,16,16,8,80,48,
                          {[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]},
                          {{[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],
                            []}}}}}}
{trace,<0.86.0>,return_to,{typechecker,glb,4}}
{trace,<0.86.0>,call,
    {typechecker,glb_ty,
        [{atom,0,map},
         {atom,0,map},
         #{{{atom,0,map},{atom,0,map}} => 0,
           {{type,0,tuple,
                [{atom,0,type},
                 {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
                 {atom,0,map},
                 {type,0,list,
                     [{user_type,
                          [{file,"erl_parse.erl"},{location,0}],
                          af_assoc_type,[]}]}]},
            {type,0,tuple,
                [{atom,0,type},
                 {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
                 {atom,0,map},
                 {atom,0,any}]}} =>
               0},
         {env,
             #{{f,1} =>
                   [{type,
                        {7,8},
                        bounded_fun,
                        [{type,
                             {7,8},
                             'fun',
                             [{type,{7,8},product,[{user_type,{7,9},type,[]}]},
                              {type,{7,20},list,[{atom,{7,21},x}]}]},
                         []]}]},
             #{},#{},
             #{module => lc,records => #{},
               types =>
                   #{{type,0} =>
                         {[],
                          {remote_type,0,
                              [{atom,{5,17},erl_parse},
                               {atom,{5,27},abstract_type},
                               []]}}}},
             false,false,true,
             [{clauses_controls,true}],
             30,
             [{type,
                  {7,8},
                  bounded_fun,
                  [{type,
                       {7,8},
                       'fun',
                       [{type,{7,8},product,[{user_type,{7,9},type,[]}]},
                        {type,{7,20},list,[{atom,{7,21},x}]}]},
                   []]}]}]}}
{trace,<0.86.0>,return_from,
       {typechecker,glb_ty,4},
       {{atom,0,map},
        {constraints,#{},#{},
                     {set,0,16,16,8,80,48,
                          {[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]},
                          {{[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],
                            []}}}}}}
{trace,<0.86.0>,return_to,{typechecker,glb,4}}
{trace,<0.86.0>,call,
    {typechecker,glb_ty,
        [{type,0,list,
             [{user_type,
                  [{file,"erl_parse.erl"},{location,0}],
                  af_assoc_type,[]}]},
         {atom,0,any},
         #{{{type,0,list,
                [{user_type,
                     [{file,"erl_parse.erl"},{location,0}],
                     af_assoc_type,[]}]},
            {atom,0,any}} =>
               0,
           {{type,0,tuple,
                [{atom,0,type},
                 {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
                 {atom,0,map},
                 {type,0,list,
                     [{user_type,
                          [{file,"erl_parse.erl"},{location,0}],
                          af_assoc_type,[]}]}]},
            {type,0,tuple,
                [{atom,0,type},
                 {user_type,[{file,"erl_parse.erl"},{location,0}],anno,[]},
                 {atom,0,map},
                 {atom,0,any}]}} =>
               0},
         {env,
             #{{f,1} =>
                   [{type,
                        {7,8},
                        bounded_fun,
                        [{type,
                             {7,8},
                             'fun',
                             [{type,{7,8},product,[{user_type,{7,9},type,[]}]},
                              {type,{7,20},list,[{atom,{7,21},x}]}]},
                         []]}]},
             #{},#{},
             #{module => lc,records => #{},
               types =>
                   #{{type,0} =>
                         {[],
                          {remote_type,0,
                              [{atom,{5,17},erl_parse},
                               {atom,{5,27},abstract_type},
                               []]}}}},
             false,false,true,
             [{clauses_controls,true}],
             30,
             [{type,
                  {7,8},
                  bounded_fun,
                  [{type,
                       {7,8},
                       'fun',
                       [{type,{7,8},product,[{user_type,{7,9},type,[]}]},
                        {type,{7,20},list,[{atom,{7,21},x}]}]},
                   []]}]}]}}
{trace,<0.86.0>,return_from,
       {typechecker,glb_ty,4},
       {{type,0,none,[]},
        {constraints,#{},#{},
                     {set,0,16,16,8,80,48,
                          {[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]},
                          {{[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],
                            []}}}}}}

@erszcz erszcz changed the title Add test/known_problems/should_pass/lc_cannot_glb_different_variants.erl Add examples of list comprehension generators being none() Aug 12, 2022
@erszcz erszcz merged commit 4248daf into josefs:master Aug 22, 2022
@erszcz erszcz deleted the lc-generators-being-none branch August 24, 2022 21:46
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@zuiderkwast zuiderkwast zuiderkwast approved these changes

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@erszcz @zuiderkwast