llvm crash - segfault during template argument deduction

[eddieavd]

llvm crashes for the following reduced code:

class a {
  using size_type = long;
  template < typename Self > void at( this Self&&, size_type );
};
template < typename > class b : a{};
template < typename T = int > class d : b< T > {
  using some_type = T;

  some_type f = at( f );
};
d i e

if some_type does not depend on T, llvm reports use of underclared identifier 'at', no crash

full preprocessed input
reproducing compile command

compiler explorer 1, compiler explorer 2

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: None (eddieavd)

llvm crashes for the following reduced code:

class a {
  using size_type = long;
  template < typename Self > void at( this Self&&, size_type );
};
template < typename > class b : a{};
template < typename T = int > class d : b< T > {
  using some_type = T;

  some_type f = at( f );
};
d i e

if some_type does not depend on T, llvm reports use of underclared identifier 'at', no crash

full preprocessed input
reproducing compile command

compiler explorer 1, compiler explorer 2

[shafik]

Looks similar to: #69838

CC @cor3ntin

[MagentaTreehouse]

@shafik Looks like it's no longer crashing.

[shafik]

@shafik Looks like it's no longer crashing.

It looks like it was fixed in clang-20