[FE 1.0] Report recursive type checker problem as a warning till 1.9

^KT-48546

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java

@@ -8086,6 +8086,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                 runTest("compiler/testData/diagnostics/tests/delegatedProperty/kt48546.kt");
             }
 
+            @Test
+            @TestMetadata("kt48546Strict.kt")
+            public void testKt48546Strict() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/delegatedProperty/kt48546Strict.kt");
+            }
+
             @Test
             @TestMetadata("localVariable.kt")
             public void testLocalVariable() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java

@@ -8086,6 +8086,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                 runTest("compiler/testData/diagnostics/tests/delegatedProperty/kt48546.kt");
             }
 
+            @Test
+            @TestMetadata("kt48546Strict.kt")
+            public void testKt48546Strict() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/delegatedProperty/kt48546Strict.kt");
+            }
+
             @Test
             @TestMetadata("localVariable.kt")
             public void testLocalVariable() throws Exception {

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java

@@ -796,7 +796,8 @@ public interface Errors {
     DiagnosticFactory1<PsiElement, String> NAME_SHADOWING = DiagnosticFactory1.create(WARNING, PositioningStrategies.FOR_REDECLARATION);
     DiagnosticFactory0<PsiElement> ACCESSOR_PARAMETER_NAME_SHADOWING = DiagnosticFactory0.create(WARNING);
 
-    DiagnosticFactoryForDeprecation0<KtExpression> TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM = DiagnosticFactoryForDeprecation0.create(LanguageFeature.ForbidRecursiveDelegateExpressions);
+    DiagnosticFactoryForDeprecation0<KtExpression> TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM =
+            DiagnosticFactoryForDeprecation0.create(LanguageFeature.ForbidRecursiveDelegateExpressions);
 
     // Checking call arguments
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/DiagnosticReporterByTrackingStrategy.kt

@@ -75,7 +75,11 @@ class DiagnosticReporterByTrackingStrategy(
                 trace,
                 (diagnostic as NoValueForParameter).parameterDescriptor
             )
-            TypeCheckerHasRanIntoRecursion::class.java -> tracingStrategy.recursiveType(trace)
+            TypeCheckerHasRanIntoRecursion::class.java -> {
+                val shouldReportErrorsOnRecursiveTypeInsidePlusAssignment =
+                    context.languageVersionSettings.supportsFeature(LanguageFeature.ReportErrorsOnRecursiveTypeInsidePlusAssignment)
+                tracingStrategy.recursiveType(trace, shouldReportErrorsOnRecursiveTypeInsidePlusAssignment)
+            }
             InstantiationOfAbstractClass::class.java -> tracingStrategy.instantiationOfAbstractClass(trace)
             AbstractSuperCall::class.java -> {
                 val superExpression = (diagnostic as AbstractSuperCall).receiver.psiExpression as? KtSuperExpression

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tasks/AbstractTracingStrategy.java

@@ -22,6 +22,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.diagnostics.Diagnostic;
+import org.jetbrains.kotlin.diagnostics.DiagnosticFactory0;
 import org.jetbrains.kotlin.diagnostics.DiagnosticUtilsKt;
 import org.jetbrains.kotlin.lexer.KtToken;
 import org.jetbrains.kotlin.lexer.KtTokens;
@@ -138,10 +139,16 @@ public abstract class AbstractTracingStrategy implements TracingStrategy {
     }
 
     @Override
-    public void recursiveType(@NotNull BindingTrace trace) {
+    public void recursiveType(@NotNull BindingTrace trace, boolean shouldReportErrorsOnRecursiveTypeInsidePlusAssignment) {
         KtExpression expression = call.getCalleeExpression();
         if (expression == null) return;
-        trace.report(TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM.getErrorFactory().on(expression));
+        DiagnosticFactory0<KtExpression> factory;
+        if (shouldReportErrorsOnRecursiveTypeInsidePlusAssignment) {
+            factory = TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM.getErrorFactory();
+        } else {
+            factory = TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM.getWarningFactory();
+        }
+        trace.report(factory.on(expression));
     }
 
     @Override

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tasks/TracingStrategy.java

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.resolve.calls.tasks;
 
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.kotlin.config.LanguageVersionSettings;
 import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.psi.Call;
 import org.jetbrains.kotlin.resolve.BindingTrace;
@@ -82,7 +83,7 @@ public interface TracingStrategy {
         ) {}
 
         @Override
-        public void recursiveType(@NotNull BindingTrace trace) {}
+        public void recursiveType(@NotNull BindingTrace trace, boolean shouldReportErrorsOnRecursiveTypeInsidePlusAssignment) {}
 
         @Override
         public void instantiationOfAbstractClass(@NotNull BindingTrace trace) {}
@@ -147,7 +148,7 @@ public interface TracingStrategy {
             @NotNull Collection<? extends ResolvedCall<D>> descriptors
     );
 
-    void recursiveType(@NotNull BindingTrace trace);
+    void recursiveType(@NotNull BindingTrace trace, boolean shouldReportErrorsOnRecursiveTypeInsidePlusAssignment);
 
     void instantiationOfAbstractClass(@NotNull BindingTrace trace);
 

compiler/frontend/src/org/jetbrains/kotlin/types/expressions/ControlStructureTypingUtils.java

@@ -585,7 +585,7 @@ public class ControlStructureTypingUtils {
         }
 
         @Override
-        public void recursiveType(@NotNull BindingTrace trace) {
+        public void recursiveType(@NotNull BindingTrace trace, boolean shouldReportErrorsOnRecursiveTypeInsidePlusAssignment) {
             logError();
         }
 

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/KotlinCallCompleter.kt

@@ -273,7 +273,7 @@ class KotlinCallCompleter(
         constraintSystem.errors.forEach(diagnosticsHolder::addError)
 
         if (returnType is ErrorType && returnType.kind == ErrorTypeKind.RECURSIVE_TYPE) {
-            diagnosticsHolder.addDiagnostic(TypeCheckerHasRanIntoRecursion(resolvedCallAtom))
+            diagnosticsHolder.addDiagnostic(TypeCheckerHasRanIntoRecursion)
         }
     }
 

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/model/KotlinCallDiagnostics.kt

@@ -116,7 +116,7 @@ class WrongCountOfTypeArguments(
     override fun report(reporter: DiagnosticReporter) = reporter.onTypeArguments(this)
 }
 
-class TypeCheckerHasRanIntoRecursion : KotlinCallDiagnostic(INAPPLICABLE) {
+object TypeCheckerHasRanIntoRecursion : KotlinCallDiagnostic(INAPPLICABLE) {
     override fun report(reporter: DiagnosticReporter) = reporter.onCall(this)
 }
 

compiler/testData/diagnostics/tests/delegatedProperty/kt48546.fir.kt

@@ -1,9 +1,10 @@
 // WITH_STDLIB
+// FIR: KT-51648
 
 object DelegateTest {
     var result = ""
     val f by lazy {
-        result += <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR!>f<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>toString<!>() // Compiler crash
+        result += <!DEBUG_INFO_EXPRESSION_TYPE("ERROR CLASS: cycle")!>f<!>.toString() // Compiler crash
         "hello"
     }
 }
@@ -11,7 +12,7 @@ object DelegateTest {
 object DelegateTest2 {
     var result = ""
     val f by lazy {
-        result += <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR!>f<!>
+        result += <!DEBUG_INFO_EXPRESSION_TYPE("ERROR CLASS: cycle")!>f<!>
         "hello"
     }
 }

compiler/testData/diagnostics/tests/delegatedProperty/kt48546.kt

@@ -1,9 +1,10 @@
 // WITH_STDLIB
+// FIR: KT-51648
 
 object DelegateTest {
     var result = ""
     val f by lazy {
-        result += <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR!>f<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>toString<!>() // Compiler crash
+        result += <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_WARNING!>f<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>toString<!>() // Compiler crash
         "hello"
     }
 }
@@ -11,7 +12,7 @@ object DelegateTest {
 object DelegateTest2 {
     var result = ""
     val f by lazy {
-        result += <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR!>f<!>
+        result += <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_WARNING!>f<!>
         "hello"
     }
 }

compiler/testData/diagnostics/tests/delegatedProperty/kt48546.txt

@@ -8,3 +8,13 @@ public object DelegateTest {
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
+
+public object DelegateTest2 {
+    private constructor DelegateTest2()
+    public final val f: kotlin.String
+    public final var result: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+

compiler/testData/diagnostics/tests/delegatedProperty/kt48546Strict.fir.kt

@@ -0,0 +1,19 @@
+// !LANGUAGE: +ReportErrorsOnRecursiveTypeInsidePlusAssignment
+// WITH_STDLIB
+// FIR: KT-51648
+
+object DelegateTest {
+    var result = ""
+    val f by lazy {
+        result += <!DEBUG_INFO_EXPRESSION_TYPE("ERROR CLASS: cycle")!>f<!>.toString() // Compiler crash
+        "hello"
+    }
+}
+
+object DelegateTest2 {
+    var result = ""
+    val f by lazy {
+        result += <!DEBUG_INFO_EXPRESSION_TYPE("ERROR CLASS: cycle")!>f<!>
+        "hello"
+    }
+}

compiler/testData/diagnostics/tests/delegatedProperty/kt48546Strict.kt

@@ -0,0 +1,19 @@
+// !LANGUAGE: +ReportErrorsOnRecursiveTypeInsidePlusAssignment
+// WITH_STDLIB
+// FIR: KT-51648
+
+object DelegateTest {
+    var result = ""
+    val f by lazy {
+        result += <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR!>f<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>toString<!>() // Compiler crash
+        "hello"
+    }
+}
+
+object DelegateTest2 {
+    var result = ""
+    val f by lazy {
+        result += <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR!>f<!>
+        "hello"
+    }
+}

compiler/testData/diagnostics/tests/delegatedProperty/kt48546Strict.txt

@@ -0,0 +1,19 @@
+package
+
+public object DelegateTest {
+    private constructor DelegateTest()
+    public final val f: kotlin.String
+    public final var result: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public object DelegateTest2 {
+    private constructor DelegateTest2()
+    public final val f: kotlin.String
+    public final var result: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/delegatedProperty/recursiveType.kt

@@ -3,12 +3,12 @@
 
 import kotlin.reflect.KProperty
 
-val a by <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR!>a<!>
+val a by <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_WARNING!>a<!>
 
 val b by Delegate(<!DEBUG_INFO_MISSING_UNRESOLVED, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR!>b<!>)
 
 val c by <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, UNINITIALIZED_VARIABLE!>d<!>
-val d by <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>c<!>
+val d by <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_WARNING!>c<!>
 
 class Delegate(i: Int) {
   operator fun getValue(t: Any?, p: KProperty<*>): Int {

compiler/testData/diagnostics/tests/delegation/kt48546.kt

@@ -3,7 +3,7 @@
 object DelegateTest {
     var result = ""
     val f by lazy {
-        result += <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR!>f<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>toString<!>() // Compiler crash
+        result += <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_WARNING!>f<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>toString<!>() // Compiler crash
         "hello"
     }
 }

compiler/testData/diagnostics/testsWithStdLib/coroutines/kt18292.kt

@@ -13,6 +13,6 @@ suspend fun fib(n: Long) =
     async {
         when {
             n < 2 -> n
-            else -> <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR!><!DEBUG_INFO_MISSING_UNRESOLVED!>fib<!>(<!DEBUG_INFO_MISSING_UNRESOLVED!>n<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>-<!> 1)<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>await<!>() <!DEBUG_INFO_MISSING_UNRESOLVED!>+<!> <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR!>fib<!>(n - 2).<!DEBUG_INFO_MISSING_UNRESOLVED!>await<!>()
+            else -> <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_ERROR!><!DEBUG_INFO_MISSING_UNRESOLVED!>fib<!>(<!DEBUG_INFO_MISSING_UNRESOLVED!>n<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>-<!> 1)<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>await<!>() <!DEBUG_INFO_MISSING_UNRESOLVED!>+<!> <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM_WARNING!>fib<!>(n - 2).<!DEBUG_INFO_MISSING_UNRESOLVED!>await<!>()
         }
     }

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java

@@ -8092,6 +8092,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/delegatedProperty/kt48546.kt");
             }
 
+            @Test
+            @TestMetadata("kt48546Strict.kt")
+            public void testKt48546Strict() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/delegatedProperty/kt48546Strict.kt");
+            }
+
             @Test
             @TestMetadata("localVariable.kt")
             public void testLocalVariable() throws Exception {

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -270,6 +270,7 @@ enum class LanguageFeature(
     ProhibitEnumDeclaringClass(KOTLIN_1_9, kind = BUG_FIX), // KT-49653
     StopPropagatingDeprecationThroughOverrides(KOTLIN_1_9, kind = BUG_FIX), // KT-47902
     ReportTypeVarianceConflictOnQualifierArguments(KOTLIN_1_9, kind = BUG_FIX), // KT-50947
+    ReportErrorsOnRecursiveTypeInsidePlusAssignment(KOTLIN_1_9, kind = BUG_FIX), // KT-48546
 
     // Disabled for indefinite time. See KT-48535 and related discussion
     ApproximateIntegerLiteralTypesInReceiverPosition(sinceVersion = null),