void methods should be ignored regardless the fact they match patterns defined. Otherwise String.getChars() method is being highlighted with default patterns.

plugins/InspectionGadgets/src/com/siyeh/ig/bugs/IgnoreResultOfCallInspection.java

@@ -131,6 +131,11 @@ public class IgnoreResultOfCallInspection extends ExpressionInspection {
                 return;
             }
 
+            final PsiType retType = method.getReturnType();
+            if (retType == PsiType.VOID) {
+                return;
+            }
+
             for (Iterator iterator = callsToCheck.iterator(); iterator.hasNext();) {
                 final ReturnCheckSpecification spec = (ReturnCheckSpecification) iterator.next();
                 final Pattern methodNamePattern = spec.getMethodNamePattern();