https://gcc.gnu.org/g:b285704c459d179906ce6eff802457a5bd673fbb
commit r16-8980-gb285704c459d179906ce6eff802457a5bd673fbb Author: Javier Miranda <[email protected]> Date: Fri Jan 16 17:11:55 2026 +0000 ada: Spurious error on formals with First_Controlling_Parameter type This patch fixes a spurious error reported by the frontend when a dispatching primitive of a tagged type has additional formals with types that have the First_Controlling_Parameter aspect. gcc/ada/ChangeLog: * sem_disp.adb (Check_Controlling_Formals): Formals of a type specifying aspect First_Controlling_Parameter are not candidate controlling parameters when they are not the first formal of the dispatching primitive. Diff: --- gcc/ada/sem_disp.adb | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/gcc/ada/sem_disp.adb b/gcc/ada/sem_disp.adb index ff606c7cfa7b..160f1a315751 100644 --- a/gcc/ada/sem_disp.adb +++ b/gcc/ada/sem_disp.adb @@ -309,7 +309,29 @@ package body Sem_Disp is -- Common Ada case if not Has_First_Controlling_Parameter_Aspect (Typ) then - Ctrl_Type := Check_Controlling_Type (Etype (Formal), Subp); + + -- Formals of a type specifying aspect First_Controlling_Parameter + -- are not candidate controlling parameters when they are not + -- the first formal of the dispatching primitive. For example: + -- + -- type T1 is tagged ... + -- type T2 is tagged ... with First_Controlling_Parameter; + -- procedure Prim (X : T1; Y : T2); + -- + -- When T2 does not have the First_Controlling_Parameter aspect + -- this example is rejected because a primitive can be dispatching + -- in only one type. However, T2 cannot be a candidate controlling + -- type for Prim because Y is not its first formal. Therefore, + -- this example is accepted. + + if Is_Tagged_Type (Etype (Formal)) + and then Has_First_Controlling_Parameter_Aspect (Etype (Formal)) + and then Formal /= First_Formal (Subp) + then + null; + else + Ctrl_Type := Check_Controlling_Type (Etype (Formal), Subp); + end if; -- Type with the First_Controlling_Parameter aspect: for overriding -- primitives of a parent type that lacks this aspect, we cannot be
