Unused assignment

Reports assignment values that are not used after assignment. If the assignment value is unused, it's better to remove the assignment to shorten the code and avoid redundant allocations.

The following cases are reported:

variables that are never read after assignment
variables that are always overwritten with a new value before being read
variable initializers that are redundant (for one of the two reasons above)

Configure the inspection:

Use the Report redundant initializers option to report redundant initializers:

int getI() {
  int i = 0; // redundant initialization
  i = 2;
  return i;
}

Use the Report prefix expressions that can be replaced with binary expressions option to report cases where an ++i expression may be replaced with i + 1:

int preInc(int value) {
  int res = value;
  return ++res;
}

Use the Report postfix expressions where the changed value is not used option to report i++ cases where the value of i is not used later:

int postInc(int value) {
  int res = value;
  return res++;
}

Use the Report pattern variables whose values are never used option to report cases where the value of a pattern variable is overwritten before it is read:

if (object instanceof String s) {
    s = "hello";
    System.out.println(s);
}

Use the Report iteration parameters whose values are never used option to report cases where the value of an iteration parameter of an enhanced for statements is overwritten before it is read:

for (String arg : args) {
    arg = "test";
    System.out.println(arg);
}

Inspection options

Option	Type	Default
Report redundant initializers	Checkbox	true
Report prefix expressions that can be replaced with a binary expression	Checkbox	false
Report postfix expressions where the changed value is not used	Checkbox	true
Report pattern variables whose values are never used	Checkbox	true
Report iteration parameters whose values are never used	Checkbox	true

Inspection Details
Available in:	IntelliJ IDEA 2023.3, Qodana for JVM 2023.3
Plugin:	Java, 233.SNAPSHOT

Last modified: 13 July 2023