[libcxx] [test] Fix the gets-removed.verify.cpp test with Clang 21

[mstorsjo]

This fixes test errors like this, at least for a mingw target, if building with Clang 21 instead of Clang 20, as in the CI environment:

# .---command stderr------------
# | error: 'expected-error' diagnostics seen but not expected:
# |   File C:\a\llvm-mingw\llvm-mingw\llvm-project\libcxx\test\std\input.output\file.streams\c.files\gets-removed.verify.cpp Line 16: cannot initialize a parameter of type 'char *' with an lvalue of type 'const char *'
# | 1 error generated.
# `-----------------------------
# error: command failed with exit status: 1

This extra, unexpected diagnostic appears in Clang 21, since commit 9eef4d1 ("Remove delayed typo expressions"). Before this, we got the expected diagnostic error: no member named 'gets' in namespace 'std', with the typo correction hint did you mean 'puts'?. After this change, we get the typo correction hint did you mean simply 'gets'? instead. And with the typo correction finding ::gets, it goes on to produce a second diagnostic about mismatched parameter for that function.

Avoid these unexpected diagnostics by passing the right type of parameter to the gets function.

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: Martin Storsjö (mstorsjo)

Changes

This fixes test errors like this, at least for a mingw target, if building with Clang 21 instead of Clang 20, as in the CI environment:

# .---command stderr------------
# | error: 'expected-error' diagnostics seen but not expected:
# |   File C:\a\llvm-mingw\llvm-mingw\llvm-project\libcxx\test\std\input.output\file.streams\c.files\gets-removed.verify.cpp Line 16: cannot initialize a parameter of type 'char *' with an lvalue of type 'const char *'
# | 1 error generated.
# `-----------------------------
# error: command failed with exit status: 1

This extra, unexpected diagnostic appears in Clang 21, since commit 9eef4d1 ("Remove delayed typo expressions"). Before this, we got the expected diagnostic error: no member named 'gets' in namespace 'std', with the typo correction hint did you mean 'puts'?. After this change, we get the typo correction hint did you mean simply 'gets'? instead. And with the typo correction finding ::gets, it goes on to produce a second diagnostic about mismatched parameter for that function.

Avoid these unexpected diagnostics by passing the right type of parameter to the gets function.

---

Full diff: https://github.com/llvm/llvm-project/pull/169235.diff

1 Files Affected:

• (modified) libcxx/test/std/input.output/file.streams/c.files/gets-removed.verify.cpp (+1-1)

diff --git a/libcxx/test/std/input.output/file.streams/c.files/gets-removed.verify.cpp b/libcxx/test/std/input.output/file.streams/c.files/gets-removed.verify.cpp
index 281ef37e92d27..fb49375a21baa 100644
--- a/libcxx/test/std/input.output/file.streams/c.files/gets-removed.verify.cpp
+++ b/libcxx/test/std/input.output/file.streams/c.files/gets-removed.verify.cpp
@@ -12,6 +12,6 @@
 
 #include <cstdio>
 
-void f(char const* str) {
+void f(char* str) {
   (void)std::gets(str); // expected-error {{no member named 'gets' in namespace 'std'}}
 }

[mstorsjo]

This fixes a new issue caught in my weekly testing of libcxx tests with a fresh nightly Clang for llvm-mingw, at https://github.com/mstorsjo/llvm-mingw/actions/runs/19612006242/job/56159201525.