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tests/lint: show bug in conditional expression (since 2021-07-15) 

Since cgram.y 1.325 from 2021-07-15, conditional expressions did not
accept a comma-expression in the then-branch anymore.  In practice, this
is an edge case though since comma expressions are rare.
This commit is contained in:
rillig 2021-07-26 18:06:43 +00:00
parent 51b2be3c67
commit 3120116ed3
2 changed files with 26 additions and 1 deletions
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26
tests/usr.bin/xlint/lint1/expr_precedence.c
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@ -1,4 +1,4 @@
/* $NetBSD: expr_precedence.c,v 1.5 2021/07/26 17:27:22 rillig Exp $ */
/* $NetBSD: expr_precedence.c,v 1.6 2021/07/26 18:06:43 rillig Exp $ */
# 3 "expr_precedence.c"
/*
@ -51,3 +51,27 @@ assignment_associativity(int arg)
left = arg;
}
void
conditional_associativity(_Bool cond1, _Bool cond2, int a, int b, int c)
{
/* The then-expression can be an arbitrary expression. */
var = cond1 ? cond2 ? a : b : c;
var = cond1 ? (cond2 ? a : b) : c;
/* The then-expression can even be a comma-expression. */
/* expect+1: error: syntax error ',' [249] *//* FIXME */
var = cond1 ? cond2 ? a, b : (b, a) : c;
var = cond1 ? a : cond2 ? b : c;
/*
* In almost all programming languages, '?:' is right-associative,
* which allows for easy chaining.
*/
var = cond1 ? a : (cond2 ? b : c);
/*
* In PHP, '?:' is left-associative, which is rather surprising and
* requires more parentheses to get the desired effect.
*/
var = (cond1 ? a : cond2) ? b : c;
}

1
tests/usr.bin/xlint/lint1/expr_precedence.exp
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@ -2,3 +2,4 @@ expr_precedence.c(15): error: syntax error '4' [249]
expr_precedence.c(18): error: non-constant initializer [177]
expr_precedence.c(35): error: 'var' undefined [99]
expr_precedence.c(35): error: syntax error '=' [249]
expr_precedence.c(64): error: syntax error ',' [249]