On 4/17/23 14:44, Patrick Palka wrote:
Here when level lowering the bound ttp TT<typename T::type> via the substitution T=C, we're neglecting to canonicalize (and therefore strip of simple typedefs) the resulting template arguments {A<int>} before determining its new canonical type via hash table lookup. This leads to an a hash mismatch ICE for the two equivalent types TT<int> and TT<A<int>> since iterative_hash_template_arg misbehaves for a non-canonicalized type argument.We can fix this by canonicalizing or coercing the substituted arguments directly, but given that creation and ordinary substitution of bound ttps both go through lookup_template_class, which in turn performs coercion/canonicalization, it seems best to make this code path go through lookup_template_class as well. Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for trunk/13?
OK.
PR c++/109531 gcc/cp/ChangeLog: * pt.cc (tsubst) <case BOUND_TEMPLATE_TEMPLATE_PARM>: In the level-lowering case just use lookup_template_class to rebuild the bound ttp. gcc/testsuite/ChangeLog: * g++.dg/template/canon-type-20.C: New test. * g++.dg/template/ttp36.C: New test. --- gcc/cp/pt.cc | 39 ++++++++++--------- gcc/testsuite/g++.dg/template/canon-type-20.C | 18 +++++++++ gcc/testsuite/g++.dg/template/ttp36.C | 12 ++++++ 3 files changed, 50 insertions(+), 19 deletions(-) create mode 100644 gcc/testsuite/g++.dg/template/canon-type-20.C create mode 100644 gcc/testsuite/g++.dg/template/ttp36.C diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index fcc8e0d1d57..e065ace5c55 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -16232,7 +16232,6 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) { case TEMPLATE_TYPE_PARM: case TEMPLATE_TEMPLATE_PARM: - case BOUND_TEMPLATE_TEMPLATE_PARM: if (cp_type_quals (t)) { r = tsubst (TYPE_MAIN_VARIANT (t), args, complain, in_decl); @@ -16274,24 +16273,6 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) only instantiated during satisfaction. */ PLACEHOLDER_TYPE_CONSTRAINTS_INFO (r) = ci;- if (code == BOUND_TEMPLATE_TEMPLATE_PARM)- { - tree tinfo = TYPE_TEMPLATE_INFO (t); - /* We might need to substitute into the types of non-type - template parameters. */ - tree tmpl = tsubst (TI_TEMPLATE (tinfo), args, - complain, in_decl); - if (tmpl == error_mark_node) - return error_mark_node; - tree argvec = tsubst (TI_ARGS (tinfo), args, - complain, in_decl); - if (argvec == error_mark_node) - return error_mark_node; - - TEMPLATE_TEMPLATE_PARM_TEMPLATE_INFO (r) - = build_template_info (tmpl, argvec); - } - if (TYPE_STRUCTURAL_EQUALITY_P (t)) SET_TYPE_STRUCTURAL_EQUALITY (r); else @@ -16299,6 +16280,26 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) } break;+ case BOUND_TEMPLATE_TEMPLATE_PARM:+ { + tree tinfo = TYPE_TEMPLATE_INFO (t); + /* We might need to substitute into the types of non-type + template parameters. This also lowers the level of + the ttp appropriately. */ + tree tmpl = tsubst (TI_TEMPLATE (tinfo), args, + complain, in_decl); + if (tmpl == error_mark_node) + return error_mark_node; + tree argvec = tsubst (TI_ARGS (tinfo), args, + complain, in_decl); + if (argvec == error_mark_node) + return error_mark_node; + r = lookup_template_class (tmpl, argvec, in_decl, NULL_TREE, + /*entering_scope=*/false, complain); + r = cp_build_qualified_type (r, cp_type_quals (t), complain); + break; + } + case TEMPLATE_PARM_INDEX: /* OK, now substitute the type of the non-type parameter. We couldn't do it earlier because it might be an auto parameter, diff --git a/gcc/testsuite/g++.dg/template/canon-type-20.C b/gcc/testsuite/g++.dg/template/canon-type-20.C new file mode 100644 index 00000000000..e40261037e5 --- /dev/null +++ b/gcc/testsuite/g++.dg/template/canon-type-20.C @@ -0,0 +1,18 @@ +// PR c++/109531 +// { dg-do compile { target c++11 } } +// { dg-additional-options "--param=hash-table-verification-limit=1000" } + +template<class T> +using A = int; + +struct B { using type = int; }; +struct C { using type = A<int>; }; + +template<class T> +struct D { + template<template<class> class TT> + TT<typename T::type> f (); +}; + +template struct D<B>; +template struct D<C>; diff --git a/gcc/testsuite/g++.dg/template/ttp36.C b/gcc/testsuite/g++.dg/template/ttp36.C new file mode 100644 index 00000000000..2df00855cf7 --- /dev/null +++ b/gcc/testsuite/g++.dg/template/ttp36.C @@ -0,0 +1,12 @@ +// Verify we propagate cv-quals when level-lowering a bound ttp. + +template<class T> +struct B { + template<template<class> class TT> + void f(const TT<T> *); + + template<template<class> class TT> + void f(TT<T> *); // { dg-bogus "cannot be overloaded" } +}; + +template struct B<int>;
