|  | RUN: %clang_cc1 -E %s -pedantic -std=c++2a | FileCheck -strict-whitespace %s | 
|  |  | 
|  | #define LPAREN() ( | 
|  | #define G(Q) 42 | 
|  | #define F1(R, X, ...)  __VA_OPT__(G R X) ) | 
|  | 1: int x = F1(LPAREN(), 0, <:-); | 
|  | // CHECK: 1: int x = 42; | 
|  |  | 
|  | #define F2(...) f(0 __VA_OPT__(,) __VA_ARGS__) | 
|  | #define EMP | 
|  | 2: F2(EMP) | 
|  | // CHECK: 2: f(0 ) | 
|  |  | 
|  | #define H3(X, ...) #__VA_OPT__(X##X X##X) | 
|  | 3: H3(, 0) | 
|  | // CHECK: 3: "" | 
|  |  | 
|  | #define H4(X, ...) __VA_OPT__(a X ## X) ## b | 
|  | 4: H4(, 1) | 
|  | // CHECK: 4: a b | 
|  |  | 
|  | #define H4B(X, ...) a ## __VA_OPT__(X ## X b) | 
|  | 4B: H4B(, 1) | 
|  | // CHECK: 4B: a b | 
|  |  | 
|  | #define H5A(...) __VA_OPT__()/**/__VA_OPT__() | 
|  | #define H5B(X) a ## X ## b | 
|  | #define H5C(X) H5B(X) | 
|  | 5: H5C(H5A()) | 
|  | // CHECK: 5: ab | 
|  |  | 
|  | namespace GH60268 { | 
|  | #define H6(X, ...) __VA_OPT__(a ## X) ## b | 
|  | 6: H6(, 1); | 
|  | // CHECK: 6: ab | 
|  | } |