fix: FinalizeMethodArguments considers unary and += expressions

src/main/java/org/openrewrite/staticanalysis/FinalizeMethodArguments.java

@@ -12,6 +12,7 @@
 
 import lombok.EqualsAndHashCode;
 import lombok.Value;
+import org.jetbrains.annotations.NotNull;
 import org.openrewrite.*;
 import org.openrewrite.internal.ListUtils;
 import org.openrewrite.java.JavaIsoVisitor;
@@ -145,6 +146,40 @@ public J.Assignment visitAssignment(J.Assignment a, AtomicBoolean hasAssignment)
 
             return assignment;
         }
+
+        // contributed as a fix for issue #176
+        @Override
+        public J.@NotNull Unary visitUnary(final J.@NotNull Unary unary, final AtomicBoolean hasAssignment) {
+            if (hasAssignment.get()) {
+                return unary;
+            }
+
+            final J.Unary u = super.visitUnary(unary, hasAssignment);
+            if (u.getOperator().isModifying() && u.getExpression() instanceof J.Identifier) {
+                final J.Identifier i = (J.Identifier) u.getExpression();
+                if (i.getSimpleName().equals(this.variable.getSimpleName())) {
+                    hasAssignment.set(true);
+                }
+            }
+            return u;
+        }
+
+        // contributed as a fix for issue  #176
+        @Override
+        public J.AssignmentOperation visitAssignmentOperation(final J.AssignmentOperation assignOp, final AtomicBoolean hasAssignment) {
+            if (hasAssignment.get()) {
+                return assignOp;
+            }
+
+            final J.AssignmentOperation a = super.visitAssignmentOperation(assignOp, hasAssignment);
+            if (a.getVariable() instanceof J.Identifier) {
+                final J.Identifier i = (J.Identifier) a.getVariable();
+                if (i.getSimpleName().equals(this.variable.getSimpleName())) {
+                    hasAssignment.set(true);
+                }
+            }
+            return a;
+        }
     }
 
     private static Statement updateParam(final Statement p) {

src/test/java/org/openrewrite/staticanalysis/FinalizeMethodArgumentsTest.java

@@ -239,4 +239,75 @@ public String getSubeventNameForCategoryGroupId(final String subeventName, final
           )
         );
     }
+
+    @Test
+    @Issue("https://github.com/openrewrite/rewrite-static-analysis/issues/176")
+    void doNotReplaceIfAssignedThroughUnaryOrAccumulator(){
+        //language=java
+        rewriteRun(java("""
+          package Test;
+
+          class Test {
+
+            protected int addFinalToThisVar(int unalteredVariable) {
+              return unalteredVariable;
+            }
+
+            protected int increment(int variableToIncrement) {
+              variableToIncrement++;
+              return variableToIncrement;
+            }
+
+            protected int preIncrement(int variableToPreIncrement) {
+              return ++variableToPreIncrement;
+            }
+
+            protected int decrement(int variableToDecrement) {
+              variableToDecrement--;
+              return variableToDecrement;
+            }
+
+            protected int preDecrement(int variableToPreDecrement) {
+              return --variableToPreDecrement;
+            }
+
+            protected int accumulate(int add, int accumulator) {
+              accumulator += add;
+              return accumulator;
+            }
+          }
+          """, """
+          package Test;
+
+          class Test {
+
+            protected int addFinalToThisVar(final int unalteredVariable) {
+              return unalteredVariable;
+            }
+
+            protected int increment(int variableToIncrement) {
+              variableToIncrement++;
+              return variableToIncrement;
+            }
+
+            protected int preIncrement(int variableToPreIncrement) {
+              return ++variableToPreIncrement;
+            }
+
+            protected int decrement(int variableToDecrement) {
+              variableToDecrement--;
+              return variableToDecrement;
+            }
+
+            protected int preDecrement(int variableToPreDecrement) {
+              return --variableToPreDecrement;
+            }
+
+            protected int accumulate(int add, int accumulator) {
+              accumulator += add;
+              return accumulator;
+            }
+          }
+          """));
+    }
 }