Really fix IDEA-75562

plugins/InspectionGadgets/src/com/siyeh/ig/assignment/ReplaceAssignmentWithOperatorAssignmentInspection.java

@@ -185,7 +185,7 @@ public class ReplaceAssignmentWithOperatorAssignmentInspection extends BaseInspe
       if (operands.length < 2) {
         return;
       }
-      if (operands.length > 2 && !ParenthesesUtils.isCommutativeBinaryOperator(polyadicExpression.getOperationTokenType())) {
+      if (operands.length > 2 && !ParenthesesUtils.isAssociativeOperation(polyadicExpression)) {
         return;
       }
       for (PsiExpression operand : operands) {

plugins/InspectionGadgets/src/com/siyeh/ig/psiutils/ParenthesesUtils.java

@@ -96,6 +96,32 @@ public class ParenthesesUtils {
              token.equals(JavaTokenType.GTGTGT));
   }
 
+  public static boolean isAssociativeOperation(PsiPolyadicExpression expression) {
+    final IElementType tokenType = expression.getOperationTokenType();
+    final PsiType type = expression.getType();
+    final PsiPrimitiveType primitiveType;
+    if (type instanceof PsiClassType) {
+      primitiveType = PsiPrimitiveType.getUnboxedType(type);
+      if (primitiveType == null) {
+        return false;
+      }
+    } else if (type instanceof PsiPrimitiveType) {
+      primitiveType = (PsiPrimitiveType)type;
+    } else {
+      return false;
+    }
+    if (JavaTokenType.PLUS == tokenType || JavaTokenType.ASTERISK == tokenType) {
+      return primitiveType != PsiType.FLOAT && primitiveType != PsiType.DOUBLE;
+    } else if (JavaTokenType.EQEQ == tokenType || JavaTokenType.NE == tokenType) {
+      return primitiveType == PsiType.BOOLEAN;
+    } else if (JavaTokenType.AND == tokenType || JavaTokenType.OR == tokenType || JavaTokenType.XOR == tokenType) {
+      return true;
+    } else if (JavaTokenType.OROR == tokenType || JavaTokenType.ANDAND == tokenType) {
+      return true;
+    }
+    return false;
+  }
+
   public static int getPrecedence(PsiExpression expression) {
     if (expression instanceof PsiThisExpression ||
         expression instanceof PsiLiteralExpression ||

plugins/InspectionGadgets/test/com/siyeh/igtest/assignment/replace_assignment_with_operator_assignment/ReplaceAssignmentWithOperatorAssignment.java

@@ -24,5 +24,8 @@ public class ReplaceAssignmentWithOperatorAssignment
 
       x = x / 2 / 4;
       x = x >> 1 >> 1;
+      x = x * 2 * 2;
+      float f = 1;
+      f = f * 2 * 2;
     }
 }

plugins/InspectionGadgets/test/com/siyeh/igtest/assignment/replace_assignment_with_operator_assignment/expected.xml

@@ -34,4 +34,11 @@
     <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Assignment replaceable with operator assignment</problem_class>
     <description>&lt;code&gt;x = x + 2 + 2 + 2&lt;/code&gt; could be simplified to 'x += 2 + 2 + 2' #loc</description>
   </problem>
+
+  <problem>
+    <file>ReplaceAssignmentWithOperatorAssignment.java</file>
+    <line>27</line>
+    <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Assignment replaceable with operator assignment</problem_class>
+    <description>&lt;code&gt;x = x * 2 * 2&lt;/code&gt; could be simplified to 'x *= 2 * 2' #loc</description>
+  </problem>
 </problems>