fix #13308: Bad AST for requires in if (danmar#7530)

Author: ludviggunne

lib/tokenlist.cpp

@@ -1034,6 +1034,8 @@ static void compilePrecedence2(Token *&tok, AST_state& state)
                 compileUnaryOp(tok, state, compileExpression);
             tok = tok2->link()->next();
         } else if (Token::simpleMatch(tok->previous(), "requires {")) {
+            tok->astOperand1(state.op.top());
+            state.op.pop();
             state.op.push(tok);
             tok = tok->link()->next();
             continue;

test/testtokenize.cpp

@@ -6853,9 +6853,10 @@ class TestTokenizer : public TestFixture {
 
     void astrequires()
     {
-        ASSERT_EQUALS("requires{ac::||= ac::", testAst("template <class a> concept b = requires { a::c; } || a::c;"));
-        ASSERT_EQUALS("requires{ac::||= a{b{||",
+        ASSERT_EQUALS("brequires{ac::||= ac::", testAst("template <class a> concept b = requires { a::c; } || a::c;"));
+        ASSERT_EQUALS("crequires{ac::||= a{b{||",
                       testAst("template <class a, class b> concept c = requires { a{} || b{}; } || a::c;"));
+        ASSERT_EQUALS("ifrequires{(", testAst("if (requires { true; }) {}")); // #13308
     }
 
     void astcast() {