Introduce call checker for `Unit`-conversions

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

@@ -24476,6 +24476,11 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirOldFronte
             runTest("compiler/testData/diagnostics/tests/unitConversion/unitConversionCompatibility.kt");
         }
 
+        @TestMetadata("unitConversionDisabledForSimpleArguments.kt")
+        public void testUnitConversionDisabledForSimpleArguments() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/unitConversion/unitConversionDisabledForSimpleArguments.kt");
+        }
+
         @TestMetadata("unitConversionForAllKinds.kt")
         public void testUnitConversionForAllKinds() throws Exception {
             runTest("compiler/testData/diagnostics/tests/unitConversion/unitConversionForAllKinds.kt");

compiler/frontend/src/org/jetbrains/kotlin/resolve/PlatformConfiguratorBase.kt

@@ -49,7 +49,8 @@ private val DEFAULT_CALL_CHECKERS = listOf(
     PrimitiveNumericComparisonCallChecker, LambdaWithSuspendModifierCallChecker,
     UselessElvisCallChecker(), ResultTypeWithNullableOperatorsChecker(), NullableVarargArgumentCallChecker,
     NamedFunAsExpressionChecker, ContractNotAllowedCallChecker, ReifiedTypeParameterSubstitutionChecker(),
-    MissingDependencySupertypeChecker.ForCalls, AbstractClassInstantiationChecker, SuspendConversionCallChecker
+    MissingDependencySupertypeChecker.ForCalls, AbstractClassInstantiationChecker, SuspendConversionCallChecker,
+    UnitConversionCallChecker
 )
 private val DEFAULT_TYPE_CHECKERS = emptyList<AdditionalTypeChecker>()
 private val DEFAULT_CLASSIFIER_USAGE_CHECKERS = listOf(

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/checkers/UnitConversionCallChecker.kt

+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.resolve.calls.checkers
+
+import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.config.LanguageFeature
+import org.jetbrains.kotlin.diagnostics.Errors
+import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
+import org.jetbrains.kotlin.resolve.calls.tower.NewResolvedCallImpl
+import org.jetbrains.kotlin.resolve.calls.tower.psiCallArgument
+
+object UnitConversionCallChecker : CallChecker {
+    override fun check(resolvedCall: ResolvedCall<*>, reportOn: PsiElement, context: CallCheckerContext) {
+        if (resolvedCall !is NewResolvedCallImpl<*>) return
+
+        if (context.languageVersionSettings.supportsFeature(LanguageFeature.UnitConversion)) return
+
+        // lambdas are working since 1.0, callable references are handled as part of reference adaptation
+        // => here we're checking only simple argument
+        val argumentsWithUnitConversion = resolvedCall.resolvedCallAtom.argumentsWithUnitConversion
+
+        for (argumentWithUnitConversion in argumentsWithUnitConversion.keys) {
+            context.trace.report(
+                Errors.UNSUPPORTED_FEATURE.on(
+                    argumentWithUnitConversion.psiCallArgument.valueArgument.asElement(),
+                    LanguageFeature.UnitConversion to context.languageVersionSettings
+                )
+            )
+        }
+    }
+}
\ No newline at end of file

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

@@ -75,6 +75,8 @@ object UnitTypeConversions : ParameterTypeConversion {
             suspendFunction = expectedParameterType.isSuspendFunctionType
         )
 
+        candidate.resolvedCall.registerArgumentWithUnitConversion(argument, nonUnitReturnedParameterType)
+
         candidate.addDiagnostic(LowerPriorityToPreserveCompatibility)
 
         return nonUnitReturnedParameterType

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

@@ -69,6 +69,7 @@ abstract class ResolvedCallAtom : ResolvedAtom() {
     abstract val knownParametersSubstitutor: TypeSubstitutor
     abstract val argumentsWithConversion: Map<KotlinCallArgument, SamConversionDescription>
     abstract val argumentsWithSuspendConversion: Map<KotlinCallArgument, UnwrappedType>
+    abstract val argumentsWithUnitConversion: Map<KotlinCallArgument, UnwrappedType>
     abstract val argumentsWithConstantConversion: Map<KotlinCallArgument, IntegerValueTypeConstant>
 }
 

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

@@ -193,6 +193,7 @@ class MutableResolvedCallAtom(
     lateinit var argumentToCandidateParameter: Map<KotlinCallArgument, ValueParameterDescriptor>
     private var samAdapterMap: HashMap<KotlinCallArgument, SamConversionDescription>? = null
     private var suspendAdapterMap: HashMap<KotlinCallArgument, UnwrappedType>? = null
+    private var unitAdapterMap: HashMap<KotlinCallArgument, UnwrappedType>? = null
     private var signedUnsignedConstantConversions: HashMap<KotlinCallArgument, IntegerValueTypeConstant>? = null
 
     val hasSamConversion: Boolean
@@ -207,6 +208,9 @@ class MutableResolvedCallAtom(
     override val argumentsWithSuspendConversion: Map<KotlinCallArgument, UnwrappedType>
         get() = suspendAdapterMap ?: emptyMap()
 
+    override val argumentsWithUnitConversion: Map<KotlinCallArgument, UnwrappedType>
+        get() = unitAdapterMap ?: emptyMap()
+
     override val argumentsWithConstantConversion: Map<KotlinCallArgument, IntegerValueTypeConstant>
         get() = signedUnsignedConstantConversions ?: emptyMap()
 
@@ -224,6 +228,13 @@ class MutableResolvedCallAtom(
         suspendAdapterMap!![argument] = convertedType
     }
 
+    fun registerArgumentWithUnitConversion(argument: KotlinCallArgument, convertedType: UnwrappedType) {
+        if (unitAdapterMap == null)
+            unitAdapterMap = hashMapOf()
+
+        unitAdapterMap!![argument] = convertedType
+    }
+
     fun registerArgumentWithConstantConversion(argument: KotlinCallArgument, convertedConstant: IntegerValueTypeConstant) {
         if (signedUnsignedConstantConversions == null)
             signedUnsignedConstantConversions = hashMapOf()

compiler/testData/diagnostics/tests/unitConversion/unitConversionCompatibility.fir.kt

+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+object Test1 {
+    fun foo(f: () -> Int) {}
+
+    object Scope {
+        fun foo(f: () -> Unit) {}
+
+        fun test(f: () -> Int) {
+            <!DEBUG_INFO_CALL("fqName: Test1.foo; typeCall: function")!>foo(f)<!>
+        }
+    }
+}
+
+object Test2 {
+    fun interface KRunnable {
+        fun run()
+    }
+
+    fun foo(f: () -> Unit) {}
+
+    object Scope1 {
+        fun foo(f: KRunnable) {}
+
+        fun test(f: () -> Int) {
+            <!DEBUG_INFO_CALL("fqName: fqName is unknown; typeCall: unresolved")!><!INAPPLICABLE_CANDIDATE!>foo<!>(f)<!>
+        }
+    }
+}

compiler/testData/diagnostics/tests/unitConversion/unitConversionCompatibility.kt

+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+object Test1 {
+    fun foo(f: () -> Int) {}
+
+    object Scope {
+        fun foo(f: () -> Unit) {}
+
+        fun test(f: () -> Int) {
+            <!DEBUG_INFO_CALL("fqName: Test1.foo; typeCall: function")!><!COMPATIBILITY_WARNING!>foo<!>(f)<!>
+        }
+    }
+}
+
+object Test2 {
+    fun interface KRunnable {
+        fun run()
+    }
+
+    fun foo(f: () -> Unit) {}
+
+    object Scope1 {
+        fun foo(f: KRunnable) {}
+
+        fun test(f: () -> Int) {
+            <!DEBUG_INFO_CALL("fqName: Test2.Scope1.foo; typeCall: function")!>foo(<!UNSUPPORTED_FEATURE!>f<!>)<!>
+        }
+    }
+}

compiler/testData/diagnostics/tests/unitConversion/unitConversionCompatibility.txt

+package
+
+public object Test1 {
+    private constructor Test1()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun foo(/*0*/ f: () -> kotlin.Int): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public object Scope {
+        private constructor Scope()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final fun foo(/*0*/ f: () -> kotlin.Unit): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public final fun test(/*0*/ f: () -> kotlin.Int): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public object Test2 {
+    private constructor Test2()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun foo(/*0*/ f: () -> kotlin.Unit): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public fun interface KRunnable {
+        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 abstract fun run(): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public object Scope1 {
+        private constructor Scope1()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final fun foo(/*0*/ f: Test2.KRunnable): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public final fun test(/*0*/ f: () -> kotlin.Int): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}

compiler/testData/diagnostics/tests/unitConversion/unitConversionDisabledForSimpleArguments.fir.kt

+// !LANGUAGE: -SuspendConversion
+// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_EXPRESSION
+
+fun foo(f: () -> Unit) {}
+
+fun bar(): Int = 0
+
+abstract class SubInt : () -> Int
+
+fun test(f: () -> String, s: SubInt) {
+    foo { "lambda" }
+    foo(::bar)
+
+    <!INAPPLICABLE_CANDIDATE!>foo<!>(f)
+    <!INAPPLICABLE_CANDIDATE!>foo<!>(s)
+}
\ No newline at end of file

compiler/testData/diagnostics/tests/unitConversion/unitConversionDisabledForSimpleArguments.kt

+// !LANGUAGE: -SuspendConversion
+// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_EXPRESSION
+
+fun foo(f: () -> Unit) {}
+
+fun bar(): Int = 0
+
+abstract class SubInt : () -> Int
+
+fun test(f: () -> String, s: SubInt) {
+    foo { "lambda" }
+    foo(::bar)
+
+    foo(<!UNSUPPORTED_FEATURE!>f<!>)
+    foo(<!UNSUPPORTED_FEATURE!>s<!>)
+}
\ No newline at end of file

compiler/testData/diagnostics/tests/unitConversion/unitConversionDisabledForSimpleArguments.txt

+package
+
+public fun bar(): kotlin.Int
+public fun foo(/*0*/ f: () -> kotlin.Unit): kotlin.Unit
+public fun test(/*0*/ f: () -> kotlin.String, /*1*/ s: SubInt): kotlin.Unit
+
+public abstract class SubInt : () -> kotlin.Int {
+    public constructor SubInt()
+    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 abstract override /*1*/ /*fake_override*/ fun invoke(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -24558,6 +24558,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTestWithFirVali
                 runTest("compiler/testData/diagnostics/tests/unitConversion/unitConversionCompatibility.kt");
             }
 
+            @TestMetadata("unitConversionDisabledForSimpleArguments.kt")
+            public void testUnitConversionDisabledForSimpleArguments() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/unitConversion/unitConversionDisabledForSimpleArguments.kt");
+            }
+
             @TestMetadata("unitConversionForAllKinds.kt")
             public void testUnitConversionForAllKinds() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/unitConversion/unitConversionForAllKinds.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java

@@ -24478,6 +24478,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/unitConversion/unitConversionCompatibility.kt");
             }
 
+            @TestMetadata("unitConversionDisabledForSimpleArguments.kt")
+            public void testUnitConversionDisabledForSimpleArguments() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/unitConversion/unitConversionDisabledForSimpleArguments.kt");
+            }
+
             @TestMetadata("unitConversionForAllKinds.kt")
             public void testUnitConversionForAllKinds() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/unitConversion/unitConversionForAllKinds.kt");