[Regression] Clang accepts a syntactically invalid use of uniform_int_distribution<>(1, );

[GINN-Imp]

Clang-trunk accepts the following code without producing any syntax error.
https://godbolt.org/z/dnW5oWY84

#include <bits/stdc++.h>
using namespace std;
int a() { 
    uniform_int_distribution<>(1, ); 
    return 0;
}

Expected (Clang 19):

<source>:4:35: error: expected expression
    4 |     uniform_int_distribution<>(1, ); 
      |                                   ^
1 error generated.
ASM generation compiler returned: 1

bisect to 925e195

[zyn0217]

Reduced to https://godbolt.org/z/EGveT313K

template <class T>
struct uniform_int_distribution {
  uniform_int_distribution(T);
};

void call() { 
  uniform_int_distribution<int>(1, ); 
}

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: None (GINN-Imp)

Clang-trunk accepts the following code without producing any syntax error. https://godbolt.org/z/dnW5oWY84 ```cpp #include <bits/stdc++.h> using namespace std; int a() { uniform_int_distribution<>(1, ); return 0; } ``` Expected (Clang 19): ``` <source>:4:35: error: expected expression 4 | uniform_int_distribution<>(1, ); | ^ 1 error generated. ASM generation compiler returned: 1 ```

bisect to 925e195

[zyn0217]

This is very unfortunate because every users of ParseExpressionList have to handle the trailing-commas now!

https://godbolt.org/z/h9zq1rh6x

void call() {
  [a(42, )]() {} ();

  int *b = new int(42, );

  struct S {
    int c;

    S() : c(42, ) {}
  };

  int d(42, );
}