Address Tomasz' comments, mostly refactoring, add tests

Author: rombirli

…g/sonar/java/checks/IncDecOnFPCheck.java …a/checks/IncDecOnFloatingPointCheck.javajava-checks/src/main/java/org/sonar/java/checks/IncDecOnFPCheck.java renamed to java-checks/src/main/java/org/sonar/java/checks/IncDecOnFloatingPointCheck.java java-checks/src/main/java/org/sonar/java/checks/IncDecOnFPCheck.java renamed to java-checks/src/main/java/org/sonar/java/checks/IncDecOnFloatingPointCheck.java

@@ -19,17 +19,23 @@
 import java.util.List;
 import org.sonar.check.Rule;
 import org.sonar.plugins.java.api.IssuableSubscriptionVisitor;
+import org.sonar.plugins.java.api.semantic.Type;
 import org.sonar.plugins.java.api.semantic.Type.Primitives;
 import org.sonar.plugins.java.api.tree.IdentifierTree;
 import org.sonar.plugins.java.api.tree.Tree;
 import org.sonar.plugins.java.api.tree.UnaryExpressionTree;
 
 @Rule(key = "S8346")
-public class IncDecOnFPCheck extends IssuableSubscriptionVisitor {
+public class IncDecOnFloatingPointCheck extends IssuableSubscriptionVisitor {
 
   @Override
   public List<Tree.Kind> nodesToVisit() {
-    return List.of(Tree.Kind.POSTFIX_INCREMENT, Tree.Kind.PREFIX_INCREMENT, Tree.Kind.POSTFIX_DECREMENT, Tree.Kind.PREFIX_DECREMENT);
+    return List.of(
+      Tree.Kind.POSTFIX_INCREMENT,
+      Tree.Kind.PREFIX_INCREMENT,
+      Tree.Kind.POSTFIX_DECREMENT,
+      Tree.Kind.PREFIX_DECREMENT
+    );
   }
 
   @Override
@@ -38,9 +44,26 @@ public void visitNode(Tree tree) {
       tree instanceof UnaryExpressionTree unaryExpr &&
         unaryExpr.expression() instanceof IdentifierTree identifier &&
         // above condition should always be true, just used to pattern match safely
-        (identifier.symbolType().isPrimitive(Primitives.FLOAT) || identifier.symbolType().isPrimitive(Primitives.DOUBLE))
+        isFloatingPoint(identifier.symbolType())
     ) {
-      reportIssue(unaryExpr, "Increment and decrement operators (++/--) should not be used with floating point variables");
+      reportIssue(
+        unaryExpr,
+        "%s operator (%s) should not be used with floating point variables".formatted(
+          isIncrement(unaryExpr) ? "Increment" : "Decrement",
+          unaryExpr.operatorToken().text()
+        )
+      );
     }
   }
+
+  private static boolean isFloatingPoint(Type type) {
+    return type.isPrimitive(Primitives.FLOAT) || type.isPrimitive(Primitives.DOUBLE);
+  }
+
+  private static boolean isIncrement(UnaryExpressionTree unaryExp) {
+    return unaryExp.is(
+      Tree.Kind.PREFIX_INCREMENT,
+      Tree.Kind.POSTFIX_INCREMENT
+    );
+  }
 }

java-checks/src/test/files/checks/IncDecOnFPCheck.java

@@ -0,0 +1,100 @@
+class A {
+  void specNonCompliantExamples() {
+    for (float i = 16_000_000; i < 17_000_000; i++) { // Noncompliant {{Increment operator (++) should not be used with floating point variables}}
+//                                             ^^^
+      // ...
+    }
+
+
+    float x = 0f;
+    double y = 1.0;
+
+    x++; // Noncompliant {{Increment operator (++) should not be used with floating point variables}}
+//  ^^^
+    y--; // Noncompliant {{Decrement operator (--) should not be used with floating point variables}}
+//  ^^^
+  }
+
+  void specCompliantExamples() {
+    for (int i = 16_000_000; i < 17_000_000; i++) { // Compliant
+      // ...
+    }
+
+    float x = 0f;
+    double y = 1.0;
+
+    x += 1.0; // Compliant
+    y -= 1.0; // Compliant
+  }
+
+  void floatIsNotCompliant() {
+    float y = 0.1f;
+    y++; // Noncompliant {{Increment operator (++) should not be used with floating point variables}}
+//  ^^^
+    ++y; // Noncompliant {{Increment operator (++) should not be used with floating point variables}}
+//  ^^^
+    y--; // Noncompliant {{Decrement operator (--) should not be used with floating point variables}}
+//  ^^^
+    --y; // Noncompliant {{Decrement operator (--) should not be used with floating point variables}}
+//  ^^^
+  }
+
+  void doubleIsNotCompliant() {
+    double y = 0.1;
+    y++; // Noncompliant {{Increment operator (++) should not be used with floating point variables}}
+//  ^^^
+    ++y; // Noncompliant {{Increment operator (++) should not be used with floating point variables}}
+//  ^^^
+    y--; // Noncompliant {{Decrement operator (--) should not be used with floating point variables}}
+//  ^^^
+    --y; // Noncompliant {{Decrement operator (--) should not be used with floating point variables}}
+//  ^^^
+  }
+
+  void intIsCompliant() {
+    int z = 0;
+    z++; // Compliant
+    ++z; // Compliant
+    z--; // Compliant
+    --z; // Compliant
+  }
+
+  void longIsCompliant() {
+    long w = 0L;
+    w++; // Compliant
+    ++w; // Compliant
+    w--; // Compliant
+    --w; // Compliant
+  }
+
+  void charIsCompliant() {
+    char c = 'a';
+    c++; // Compliant
+    ++c; // Compliant
+    c--; // Compliant
+    --c; // Compliant
+  }
+
+  void otherOperatorsNotAffected() {
+    float f = 1f;
+    // test unary operator -
+    float g = -f; // compliant
+    // test binary operators just in case
+    float h = f + 1f; // compliant
+  }
+
+  // variable shadowing test
+  private double d = 3.4;
+
+  void variableShadowingTestCompliant() {
+    for (int d = 0; d < 10; d++) { // Compliant
+    }
+  }
+  // variable shadowing test
+  private int i = 3;
+
+  void variableShadowingTestCompliant() {
+    for (float i = 0; i < 10; i++) { // Noncompliant {{Increment operator (++) should not be used with floating point variables}}
+    }
+  }
+}

java-checks/src/test/files/checks/IncDecOnFloatingPointCheck.java

@@ -19,13 +19,21 @@
 import org.junit.jupiter.api.Test;
 import org.sonar.java.checks.verifier.CheckVerifier;
 
-class IncDecOnFPCheckTest {
+class IncDecOnFloatingPointCheckTest {
 
   @Test
-  void detected() {
+  void test() {
     CheckVerifier.newVerifier()
-      .onFile("src/test/files/checks/IncDecOnFPCheck.java")
-      .withCheck(new IncDecOnFPCheck())
+      .onFile("src/test/files/checks/IncDecOnFloatingPointCheck.java")
+      .withCheck(new IncDecOnFloatingPointCheck())
+      .verifyIssues();
+  }
+  @Test
+  void testNoSemantic() {
+    CheckVerifier.newVerifier()
+      .withoutSemantic()
+      .onFile("src/test/files/checks/IncDecOnFloatingPointCheck.java")
+      .withCheck(new IncDecOnFloatingPointCheck())
       .verifyIssues();
   }
 }