Simplify boolean == true / false is no longer applicable on flexible boolean #KT-15087 Fixed

idea/src/org/jetbrains/kotlin/idea/intentions/SimplifyBooleanWithConstantsIntention.kt

@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.lexer.KtTokens.*
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.resolve.CompileTimeConstantUtils
 import org.jetbrains.kotlin.resolve.calls.callUtil.getType
+import org.jetbrains.kotlin.types.isFlexible
 
 class SimplifyBooleanWithConstantsInspection : IntentionBasedInspection<KtBinaryExpression>(SimplifyBooleanWithConstantsIntention::class)
 
@@ -136,7 +137,7 @@ class SimplifyBooleanWithConstantsIntention : SelfTargetingOffsetIndependentInte
 
     private fun KtExpression?.hasBooleanType(): Boolean {
         val type = this?.getType(this.analyze()) ?: return false
-        return KotlinBuiltIns.isBoolean(type)
+        return KotlinBuiltIns.isBoolean(type) && !type.isFlexible()
     }
 
     private fun KtExpression.canBeReducedToBooleanConstant(constant: Boolean? = null): Boolean {

idea/testData/intentions/simplifyBooleanWithConstants/flexibleBoolean.1.java

@@ -0,0 +1,5 @@
+class FromJava {
+    static Boolean foo() {
+        return Boolean.TRUE;
+    }
+}

idea/testData/intentions/simplifyBooleanWithConstants/flexibleBoolean.kt

@@ -0,0 +1,4 @@
+// IS_APPLICABLE: false
+// WITH_RUNTIME
+
+fun bar() = <caret>FromJava.foo() == true

idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java

@@ -12939,6 +12939,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("flexibleBoolean.kt")
+        public void testFlexibleBoolean() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/simplifyBooleanWithConstants/flexibleBoolean.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("inapplicableNoConstants.kt")
         public void testInapplicableNoConstants() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/simplifyBooleanWithConstants/inapplicableNoConstants.kt");