https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105289
Bug ID: 105289
Summary: ICE on partial specialization
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: michsteinb at gmail dot com
Target Milestone: ---
Created attachment 52818
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52818&action=edit
Self-contained reproduction of the ICE, compile with -std=c++20
arm-none-eabi-g++ 11.2 crashes on attached self-contained code with following
prompt on win64:
```
PS H:\projects\install\arm-embedded-gcc\11.2-2022.02\bin>
.\arm-none-eabi-g++.exe -save-temps -std=c++20 -c repro.cxx
repro.cxx:14:8: internal compiler error: Segmentation fault
14 | struct push_front_vlist<XList<T, Vs...>, Arg>
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://bugs.linaro.org/> for instructions.
```
The 10.x release cycle compilers accepted this code, so does clang, so this is
a regression introduced with 11.0.
Further checks on godbolt showed the same behaviour on all 11.x compilers I
tried.
The problem stems from the primary template using a meta-function of its first
parameter as type for its second. If I do not constrain the type of Arg, the
crash disappears.
