LANG.STRUCT.PARENS : Missing Parentheses

Summary

An expression is not sufficiently parenthesized, so does not meet the explicit operator precendece requirements of Misra2012:12.1, Misra2004:12.1, and MisraC++2008:5-0-2. In particular, either:

• The sizeof operator is applied to an unparenthesized operand,
  or
• an expression has precedence in the range [2..12], and has an unparenthesized subexpression whose precedence is both greater than that of the expression and less than 13. (Where the precedence of an expression is the precedence of the operator or operand at the root of its parse tree.)

For the purposes of this warning class, operator precedences are as specified in Misra2012:12.1:

Description	Operator or Operand	Precedence
Primary	identifier, constant, string literal, ( expression )	16 (high)
Postfix	[] () (function call) . -> ++ (post-increment) -- (post-decrement) () {} (C99: compound literal)	15
Unary	++ (pre-increment) -- (pre-decrement) & * + - ~ ! sizeof defined (preprocessor)	14
Cast	()	13
Multiplicative	* / %	12
Additive	+ -	11
Bitwise shift	<< >>	10
Relational	< > <= >=	9
Equality	== !=	8
Bitwise AND	&	7
Bitwise XOR	^	6
Bitwise OR	|	5
Logical AND	&&	4
Logical OR	||	3
Conditional	?:	2
Assignment	= *= /= %= += -= <<= >>= &= ^= |=	1
Comma	,	0 (low)

Properties

RETAIN_UNNORMALIZED_C_AST = Yes
WARNING_FILTER += allow class="Missing Parentheses"

Example

#include <stddef.h>

int lang_struct_parens(void){
    int x=1;
    size_t s,t;

    s = sizeof x;   /* 'Missing Parentheses' warning issued here */
    t = sizeof(x);                  /* sizeof argument parenthesized */

    x = x << t + s; /* 'Missing Parentheses' warning issued here */
    x += x << (t + s);              /* sub-expression parenthesized */

    return x;
}

Relevant Configuration File Parameters

The following configuration file parameters affect checks for this warning class.

• REPORT_SIMILAR_WARNINGS
• RETAIN_UNNORMALIZED_C_AST
• WARNING_FILTER