Support suspend conversion in callable reference adaptation

#KT-15917 In Progress

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

@@ -23011,6 +23011,11 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirOldFronte
             runTest("compiler/testData/diagnostics/tests/suspendConversion/basicSuspendConversion.kt");
         }
 
+        @TestMetadata("basicSuspendConversionForCallableReference.kt")
+        public void testBasicSuspendConversionForCallableReference() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/suspendConversion/basicSuspendConversionForCallableReference.kt");
+        }
+
         @TestMetadata("basicSuspendConversionGenerics.kt")
         public void testBasicSuspendConversionGenerics() throws Exception {
             runTest("compiler/testData/diagnostics/tests/suspendConversion/basicSuspendConversionGenerics.kt");
@@ -23025,6 +23030,16 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirOldFronte
         public void testSuspendConversionDisabled() throws Exception {
             runTest("compiler/testData/diagnostics/tests/suspendConversion/suspendConversionDisabled.kt");
         }
+
+        @TestMetadata("suspendConversionWithFunInterfaces.kt")
+        public void testSuspendConversionWithFunInterfaces() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/suspendConversion/suspendConversionWithFunInterfaces.kt");
+        }
+
+        @TestMetadata("suspendConversionWithReferenceAdaptation.kt")
+        public void testSuspendConversionWithReferenceAdaptation() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/suspendConversion/suspendConversionWithReferenceAdaptation.kt");
+        }
     }
 
     @TestMetadata("compiler/testData/diagnostics/tests/syntheticExtensions")

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

@@ -75,9 +75,14 @@ class CallableReferenceAdaptation(
     val argumentTypes: Array<KotlinType>,
     val coercionStrategy: CoercionStrategy,
     val defaults: Int,
-    val mappedArguments: Map<ValueParameterDescriptor, ResolvedCallArgument>
+    val mappedArguments: Map<ValueParameterDescriptor, ResolvedCallArgument>,
+    val suspendConversionStrategy: SuspendConversionStrategy
 )
 
+enum class SuspendConversionStrategy {
+    SUSPEND_CONVERSION, NO_CONVERSION
+}
+
 /**
  * cases: class A {}, class B { companion object }, object C, enum class D { E }
  * A::foo <-> Type
@@ -332,10 +337,21 @@ class CallableReferencesCandidateFactory(
             else
                 mappedArguments
 
+        val suspendConversionStrategy =
+            if (
+                callComponents.languageVersionSettings.supportsFeature(LanguageFeature.SuspendConversion) &&
+                !descriptor.isSuspend && expectedType?.isSuspendFunctionType == true
+            ) {
+                SuspendConversionStrategy.SUSPEND_CONVERSION
+            } else {
+                SuspendConversionStrategy.NO_CONVERSION
+            }
+
         return CallableReferenceAdaptation(
             @Suppress("UNCHECKED_CAST") (mappedArgumentTypes as Array<KotlinType>),
             coercion, defaults,
-            adaptedArguments
+            adaptedArguments,
+            suspendConversionStrategy
         )
     }
 
@@ -428,9 +444,12 @@ class CallableReferencesCandidateFactory(
                         descriptorReturnType
                 }
 
+                val suspendConversionStrategy = callableReferenceAdaptation?.suspendConversionStrategy
+                val isSuspend = descriptor.isSuspend || suspendConversionStrategy == SuspendConversionStrategy.SUSPEND_CONVERSION
+
                 return callComponents.reflectionTypes.getKFunctionType(
                     Annotations.EMPTY, null, argumentsAndReceivers, null,
-                    returnType, descriptor.builtIns, descriptor.isSuspend
+                    returnType, descriptor.builtIns, isSuspend
                 ) to callableReferenceAdaptation
             }
             else -> return ErrorUtils.createErrorType("Unsupported descriptor type: $descriptor") to null

compiler/testData/diagnostics/tests/suspendConversion/basicSuspendConversionForCallableReference.fir.kt

@@ -0,0 +1,18 @@
+// !LANGUAGE: +SuspendConversion
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+fun foo1(f: suspend () -> Unit) {}
+fun bar1() {}
+
+fun <T> foo2(e: T, f: suspend (T) -> Unit) {}
+fun bar2(x: Int) {}
+fun bar2(s: String) {}
+
+fun test() {
+    <!INAPPLICABLE_CANDIDATE!>foo1<!>(::bar1)
+
+    <!INAPPLICABLE_CANDIDATE!>foo2<!>(42, <!UNRESOLVED_REFERENCE!>::bar2<!>)
+    <!INAPPLICABLE_CANDIDATE!>foo2<!>("str", <!UNRESOLVED_REFERENCE!>::bar2<!>)
+
+    <!INAPPLICABLE_CANDIDATE!>foo2<!>(42, ::bar1)
+}

compiler/testData/diagnostics/tests/suspendConversion/basicSuspendConversionForCallableReference.kt

@@ -0,0 +1,18 @@
+// !LANGUAGE: +SuspendConversion
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+fun foo1(f: suspend () -> Unit) {}
+fun bar1() {}
+
+fun <T> foo2(e: T, f: suspend (T) -> Unit) {}
+fun bar2(x: Int) {}
+fun bar2(s: String) {}
+
+fun test() {
+    foo1(::bar1)
+
+    foo2(42, ::bar2)
+    foo2("str", ::bar2)
+
+    foo2(42, <!TYPE_MISMATCH!>::bar1<!>)
+}

compiler/testData/diagnostics/tests/suspendConversion/basicSuspendConversionForCallableReference.txt

@@ -0,0 +1,8 @@
+package
+
+public fun bar1(): kotlin.Unit
+public fun bar2(/*0*/ x: kotlin.Int): kotlin.Unit
+public fun bar2(/*0*/ s: kotlin.String): kotlin.Unit
+public fun foo1(/*0*/ f: suspend () -> kotlin.Unit): kotlin.Unit
+public fun </*0*/ T> foo2(/*0*/ e: T, /*1*/ f: suspend (T) -> kotlin.Unit): kotlin.Unit
+public fun test(): kotlin.Unit

compiler/testData/diagnostics/tests/suspendConversion/suspendConversionWithFunInterfaces.fir.kt

@@ -0,0 +1,21 @@
+// !LANGUAGE: +SuspendConversion
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+fun interface SuspendRunnable {
+    suspend fun invoke()
+}
+
+fun foo1(s: SuspendRunnable) {}
+fun bar1() {}
+
+fun bar2(s: String = ""): Int = 0
+
+fun bar3() {}
+suspend fun bar3(s: String = ""): Int = 0
+
+fun test() {
+    <!INAPPLICABLE_CANDIDATE!>foo1<!>(::bar1)
+    <!INAPPLICABLE_CANDIDATE!>foo1<!>(::bar2)
+
+    <!INAPPLICABLE_CANDIDATE!>foo1<!>(<!UNRESOLVED_REFERENCE!>::bar3<!>) // Should be ambiguity
+}

compiler/testData/diagnostics/tests/suspendConversion/suspendConversionWithFunInterfaces.kt

@@ -0,0 +1,21 @@
+// !LANGUAGE: +SuspendConversion
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+fun interface SuspendRunnable {
+    suspend fun invoke()
+}
+
+fun foo1(s: SuspendRunnable) {}
+fun bar1() {}
+
+fun bar2(s: String = ""): Int = 0
+
+fun bar3() {}
+suspend fun bar3(s: String = ""): Int = 0
+
+fun test() {
+    foo1(::bar1)
+    foo1(::bar2)
+
+    foo1(::bar3) // Should be ambiguity
+}

compiler/testData/diagnostics/tests/suspendConversion/suspendConversionWithFunInterfaces.txt

@@ -0,0 +1,15 @@
+package
+
+public fun bar1(): kotlin.Unit
+public fun bar2(/*0*/ s: kotlin.String = ...): kotlin.Int
+public fun bar3(): kotlin.Unit
+public suspend fun bar3(/*0*/ s: kotlin.String = ...): kotlin.Int
+public fun foo1(/*0*/ s: SuspendRunnable): kotlin.Unit
+public fun test(): kotlin.Unit
+
+public fun interface SuspendRunnable {
+    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 suspend fun invoke(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/suspendConversion/suspendConversionWithReferenceAdaptation.fir.kt

@@ -0,0 +1,21 @@
+// !LANGUAGE: +SuspendConversion
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+fun unitCoercion(f: suspend () -> Unit) {}
+fun foo(): Int = 0
+
+fun defaults(f: suspend (Int) -> String) {}
+fun bar(i: Int, l: Long = 42L): String = ""
+
+fun varargs(f: suspend (Int, Int, Int) -> String) {}
+fun baz(vararg ints: Int): String = ""
+
+fun unitCoercionAndDefaults(f: suspend () -> Unit) {}
+fun all(s: String = ""): Int = 0
+
+fun test() {
+    <!INAPPLICABLE_CANDIDATE!>unitCoercion<!>(::foo)
+    <!INAPPLICABLE_CANDIDATE!>defaults<!>(::bar)
+    <!INAPPLICABLE_CANDIDATE!>varargs<!>(::baz)
+    <!INAPPLICABLE_CANDIDATE!>unitCoercionAndDefaults<!>(::all)
+}

compiler/testData/diagnostics/tests/suspendConversion/suspendConversionWithReferenceAdaptation.kt

@@ -0,0 +1,21 @@
+// !LANGUAGE: +SuspendConversion
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+fun unitCoercion(f: suspend () -> Unit) {}
+fun foo(): Int = 0
+
+fun defaults(f: suspend (Int) -> String) {}
+fun bar(i: Int, l: Long = 42L): String = ""
+
+fun varargs(f: suspend (Int, Int, Int) -> String) {}
+fun baz(vararg ints: Int): String = ""
+
+fun unitCoercionAndDefaults(f: suspend () -> Unit) {}
+fun all(s: String = ""): Int = 0
+
+fun test() {
+    unitCoercion(::foo)
+    defaults(::bar)
+    varargs(::baz)
+    unitCoercionAndDefaults(::all)
+}

compiler/testData/diagnostics/tests/suspendConversion/suspendConversionWithReferenceAdaptation.txt

@@ -0,0 +1,11 @@
+package
+
+public fun all(/*0*/ s: kotlin.String = ...): kotlin.Int
+public fun bar(/*0*/ i: kotlin.Int, /*1*/ l: kotlin.Long = ...): kotlin.String
+public fun baz(/*0*/ vararg ints: kotlin.Int /*kotlin.IntArray*/): kotlin.String
+public fun defaults(/*0*/ f: suspend (kotlin.Int) -> kotlin.String): kotlin.Unit
+public fun foo(): kotlin.Int
+public fun test(): kotlin.Unit
+public fun unitCoercion(/*0*/ f: suspend () -> kotlin.Unit): kotlin.Unit
+public fun unitCoercionAndDefaults(/*0*/ f: suspend () -> kotlin.Unit): kotlin.Unit
+public fun varargs(/*0*/ f: suspend (kotlin.Int, kotlin.Int, kotlin.Int) -> kotlin.String): kotlin.Unit

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

@@ -23093,6 +23093,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTestWithFirVali
                 runTest("compiler/testData/diagnostics/tests/suspendConversion/basicSuspendConversion.kt");
             }
 
+            @TestMetadata("basicSuspendConversionForCallableReference.kt")
+            public void testBasicSuspendConversionForCallableReference() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/suspendConversion/basicSuspendConversionForCallableReference.kt");
+            }
+
             @TestMetadata("basicSuspendConversionGenerics.kt")
             public void testBasicSuspendConversionGenerics() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/suspendConversion/basicSuspendConversionGenerics.kt");
@@ -23107,6 +23112,16 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTestWithFirVali
             public void testSuspendConversionDisabled() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/suspendConversion/suspendConversionDisabled.kt");
             }
+
+            @TestMetadata("suspendConversionWithFunInterfaces.kt")
+            public void testSuspendConversionWithFunInterfaces() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/suspendConversion/suspendConversionWithFunInterfaces.kt");
+            }
+
+            @TestMetadata("suspendConversionWithReferenceAdaptation.kt")
+            public void testSuspendConversionWithReferenceAdaptation() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/suspendConversion/suspendConversionWithReferenceAdaptation.kt");
+            }
         }
 
         @TestMetadata("compiler/testData/diagnostics/tests/syntheticExtensions")

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

@@ -23013,6 +23013,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/suspendConversion/basicSuspendConversion.kt");
             }
 
+            @TestMetadata("basicSuspendConversionForCallableReference.kt")
+            public void testBasicSuspendConversionForCallableReference() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/suspendConversion/basicSuspendConversionForCallableReference.kt");
+            }
+
             @TestMetadata("basicSuspendConversionGenerics.kt")
             public void testBasicSuspendConversionGenerics() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/suspendConversion/basicSuspendConversionGenerics.kt");
@@ -23027,6 +23032,16 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
             public void testSuspendConversionDisabled() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/suspendConversion/suspendConversionDisabled.kt");
             }
+
+            @TestMetadata("suspendConversionWithFunInterfaces.kt")
+            public void testSuspendConversionWithFunInterfaces() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/suspendConversion/suspendConversionWithFunInterfaces.kt");
+            }
+
+            @TestMetadata("suspendConversionWithReferenceAdaptation.kt")
+            public void testSuspendConversionWithReferenceAdaptation() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/suspendConversion/suspendConversionWithReferenceAdaptation.kt");
+            }
         }
 
         @TestMetadata("compiler/testData/diagnostics/tests/syntheticExtensions")