https://gcc.gnu.org/g:4b6b4e9d3bde8ea71d65a4ae83ac522c8396b919
commit r17-1360-g4b6b4e9d3bde8ea71d65a4ae83ac522c8396b919 Author: Eric Botcazou <[email protected]> Date: Mon May 25 22:40:20 2026 +0200 ada: Reject structural instantiation in generic formal part The structural instance would amount to a formal package in this context, and that's totally unsupported by the current implementation. gcc/ada/ChangeLog: * sem_ch3.adb (Analyze_Private_Extension_Declaration): Be prepared for Find_Type_Of_Subtype_Indic returning no type. * sem_ch4.adb (Process_Generic_Instantiation): Give an error if the generic instantation is referenced in a generic formal part. * sem_ch12.adb (Analyze_Formal_Derived_Type): Return early in every case of serious errors. Diff: --- gcc/ada/sem_ch12.adb | 3 +-- gcc/ada/sem_ch3.adb | 5 +++++ gcc/ada/sem_ch4.adb | 34 ++++++++++++++++++++++++++++++++++ 3 files changed, 40 insertions(+), 2 deletions(-) diff --git a/gcc/ada/sem_ch12.adb b/gcc/ada/sem_ch12.adb index 600e3f055b1b..914df9d8d489 100644 --- a/gcc/ada/sem_ch12.adb +++ b/gcc/ada/sem_ch12.adb @@ -3220,8 +3220,7 @@ package body Sem_Ch12 is end if; end if; - if Subtype_Mark (Def) in Empty | Error then - pragma Assert (Serious_Errors_Detected > 0); + if Serious_Errors_Detected > 0 then -- avoid passing bad argument to Entity return; end if; diff --git a/gcc/ada/sem_ch3.adb b/gcc/ada/sem_ch3.adb index 18bcf5181fae..180bd30c0df5 100644 --- a/gcc/ada/sem_ch3.adb +++ b/gcc/ada/sem_ch3.adb @@ -5578,6 +5578,11 @@ package body Sem_Ch3 is end if; Parent_Type := Find_Type_Of_Subtype_Indic (Indic); + if No (Parent_Type) then + pragma Assert (Serious_Errors_Detected > 0); + goto Leave; + end if; + Parent_Base := Base_Type (Parent_Type); if Parent_Type = Any_Type or else Etype (Parent_Type) = Any_Type then diff --git a/gcc/ada/sem_ch4.adb b/gcc/ada/sem_ch4.adb index 1ea77679ef31..6e7828b99774 100644 --- a/gcc/ada/sem_ch4.adb +++ b/gcc/ada/sem_ch4.adb @@ -3068,8 +3068,42 @@ package body Sem_Ch4 is Act_List : List_Id; Expr : Node_Id; Inst_Id : Entity_Id; + Par : Node_Id; + Prev_Par : Node_Id; begin + Prev_Par := N; + Par := Parent (N); + + -- A structural instance cannot be used as a formal package with the + -- current implementation of structural instantiation. + + while Present (Par) loop + if Nkind (Par) in N_Generic_Declaration + and then Is_List_Member (Prev_Par) + and then + Generic_Formal_Declarations (Par) = List_Containing (Prev_Par) + then + Error_Msg_N + ("structural instantiation cannot be used in generic formal" + & " part", N); + Rewrite (N, + Make_Raise_Program_Error (Sloc (N), + Reason => PE_Explicit_Raise)); + Analyze (N); + return; + + else + -- Prevent the search from going too far + + exit when Is_Statement (Par) + or else Is_Body_Or_Package_Declaration (Par); + end if; + + Prev_Par := Par; + Par := Parent (Par); + end loop; + Act_List := New_List; Expr := First (Expressions (N)); while Present (Expr) loop
