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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