RedundantCastUtil: report safe widening primitive casts

Fixes IDEA-154832 IDEA add unnecessary cast to double on method inline

GitOrigin-RevId: 1e8dbd1466f74bdab9584a860f4e188b025fba1c

java/java-psi-api/src/com/intellij/psi/util/RedundantCastUtil.java

@@ -761,7 +761,7 @@ public class RedundantCastUtil {
     PsiType castType = typeElement.getType();
     if (castType instanceof PsiPrimitiveType) {
       if (opType instanceof PsiPrimitiveType) {
-        return !opType.equals(castType); // let's suppose all not equal primitive casts are necessary
+        return !TypeConversionUtil.isSafeConversion(castType, opType); // let's suppose that casts losing precision are important 
       }
       final PsiPrimitiveType unboxedOpType = PsiPrimitiveType.getUnboxedType(opType);
       if (unboxedOpType != null && !unboxedOpType.equals(castType) ) {

java/java-tests/testData/inspection/redundantCast/generics/PrimitiveWidening.java

@@ -0,0 +1,18 @@
+import org.jetbrains.annotations.*;
+
+class A {
+  double widen(int x) {
+    return (<warning descr="Casting 'x' to 'double' is redundant">double</warning>) x;
+  }
+  
+  double widenDataLoss(long x) {
+    return (double) x;
+  }
+  
+  void call(short a, byte b, long c) {
+    widen((<warning descr="Casting 'a' to 'int' is redundant">int</warning>)a);
+    widen((<warning descr="Casting 'b' to 'int' is redundant">int</warning>)b);
+    widen((int)c);
+  }
+  
+}

java/java-tests/testData/refactoring/inlineMethod/WidenArgument.java

@@ -0,0 +1,12 @@
+class UnnecessaryDoubleCast {
+  public void check() {
+    <caret>eq(25, 25.49);
+  }
+
+  private static void eq(double expected, double actual) {
+    assertDoubleEquals(expected, actual);
+  }
+
+  public static void assertDoubleEquals(double v, double v2) {
+  }
+}

java/java-tests/testData/refactoring/inlineMethod/WidenArgument.java.after

@@ -0,0 +1,8 @@
+class UnnecessaryDoubleCast {
+  public void check() {
+      assertDoubleEquals(25, 25.49);
+  }
+
+    public static void assertDoubleEquals(double v, double v2) {
+  }
+}

java/java-tests/testSrc/com/intellij/java/codeInspection/RedundantCast15Test.java

@@ -78,4 +78,6 @@ public class RedundantCast15Test extends LightCodeInsightFixtureTestCase {
     myFixture.testHighlighting(getTestName(false) + ".java");
   }
   public void testDifferentNullness() { doTest();}
+
+  public void testPrimitiveWidening() { doTest(); }
 }

java/java-tests/testSrc/com/intellij/java/refactoring/inline/InlineMethodTest.java

@@ -422,6 +422,10 @@ public class InlineMethodTest extends LightRefactoringTestCase {
   public void testPrivateFieldInSuperClassInSameFile() {
     doTest();
   }
+  
+  public void testWidenArgument() {
+    doTest();
+  }
 
   public void testInlineMultipleOccurrencesInFieldInitializer() {
     doTest();