NI: don't try to infer visible lambda parameters, if there is single one – extension parameter

^KT-37038 Fixed

compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirOldFrontendDiagnosticsTestGenerated.java

@@ -9946,6 +9946,11 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirOldFronte
             runTest("compiler/testData/diagnostics/tests/inference/expectedTypeWithGenerics.kt");
         }
 
+        @TestMetadata("extensionLambdasAndArrow.kt")
+        public void testExtensionLambdasAndArrow() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/inference/extensionLambdasAndArrow.kt");
+        }
+
         @TestMetadata("findViewById.kt")
         public void testFindViewById() throws Exception {
             runTest("compiler/testData/diagnostics/tests/inference/findViewById.kt");

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

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.resolve.calls.inference.components
 
 import org.jetbrains.kotlin.builtins.isBuiltinFunctionalType
 import org.jetbrains.kotlin.builtins.isBuiltinFunctionalTypeOrSubtype
+import org.jetbrains.kotlin.builtins.isExtensionFunctionType
 import org.jetbrains.kotlin.resolve.calls.components.transformToResolvedLambda
 import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemBuilder
 import org.jetbrains.kotlin.resolve.calls.inference.model.*
@@ -172,7 +173,7 @@ class KotlinConstraintSystemCompleter(
         val atomToAnalyze = when (postponedAtom) {
             is PostponedCallableReferenceAtom -> postponedAtom.preparePostponedAtomWithTypeVariableAsExpectedType(
                 c, csBuilder, expectedTypeVariable,
-                condition = { true },
+                parameterTypes = null,
                 isSuitable = KotlinType::isBuiltinFunctionalTypeOrSubtype,
                 typeVariableCreator = { TypeVariableForCallableReferenceReturnType(builtIns, "_Q") },
                 newAtomCreator = { returnVariable, expectedType ->
@@ -183,7 +184,7 @@ class KotlinConstraintSystemCompleter(
             )
             is LambdaWithTypeVariableAsExpectedTypeAtom -> postponedAtom.preparePostponedAtomWithTypeVariableAsExpectedType(
                 c, csBuilder, expectedTypeVariable,
-                condition = { it.atom.parametersTypes?.all { type -> type != null } != true },
+                parameterTypes = postponedAtom.atom.parametersTypes,
                 isSuitable = KotlinType::isBuiltinFunctionalType,
                 typeVariableCreator = { TypeVariableForLambdaReturnType(postponedAtom.atom, builtIns, "_R") },
                 newAtomCreator = { returnVariable, expectedType ->
@@ -200,17 +201,19 @@ class KotlinConstraintSystemCompleter(
         c: Context,
         csBuilder: ConstraintSystemBuilder,
         variable: TypeConstructor,
-        condition: (T) -> Boolean,
+        parameterTypes: Array<out KotlinType?>?,
         isSuitable: KotlinType.() -> Boolean,
         typeVariableCreator: () -> V,
         newAtomCreator: (V, SimpleType) -> PostponedResolvedAtom
     ): PostponedResolvedAtom {
-        if (!condition(this)) return this
         val functionalType = resultTypeResolver.findResultType(
             c,
             c.notFixedTypeVariables.getValue(variable),
             TypeVariableDirectionCalculator.ResolveDirection.TO_SUPERTYPE
         ) as KotlinType
+        val isExtensionWithoutParameters =
+            functionalType.isExtensionFunctionType && functionalType.arguments.size == 2 && parameterTypes?.isEmpty() == true
+        if (parameterTypes?.all { type -> type != null } == true && !isExtensionWithoutParameters) return this
         if (!functionalType.isSuitable()) return this
         val returnVariable = typeVariableCreator()
         csBuilder.registerVariable(returnVariable)

compiler/testData/diagnostics/tests/inference/extensionLambdasAndArrow.fir.kt

@@ -0,0 +1,10 @@
+// !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_ANONYMOUS_PARAMETER
+
+fun main() {
+    val x1: String.() -> String = if (true) {{ this }} else {{ this }}
+    val x2: String.() -> String = if (true) {{ -> this }} else {{ -> this }}
+    val x3: () -> String = if (true) {{ -> "this" }} else {{ -> "this" }}
+    val x4: String.() -> String = if (true) {{ str: String -> "this" }} else {{ str: String -> "this" }}
+    val x5: String.() -> String = if (true) {{ str -> "this" }} else {{ str -> "this" }}
+    val x6: String.() -> String = if (true) {{ str -> "this" }} else {{ "this" }}
+}

compiler/testData/diagnostics/tests/inference/extensionLambdasAndArrow.kt

@@ -0,0 +1,14 @@
+// !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_ANONYMOUS_PARAMETER
+
+fun <T> select(vararg x: T) = x[0]
+
+fun main() {
+    val x1: String.() -> String = if (true) {{ this }} else {{ this }}
+    val x2: String.() -> String = if (true) {{ -> this }} else {{ -> this }}
+    val x3: () -> String = if (true) {{ -> "this" }} else {{ -> "this" }}
+    val x4: String.() -> String = if (true) {{ str: String -> "this" }} else {{ str: String -> "this" }}
+    val x5: String.() -> String = if (true) <!TYPE_MISMATCH!>{{ <!CANNOT_INFER_PARAMETER_TYPE, EXPECTED_PARAMETERS_NUMBER_MISMATCH!>str<!> -> "this" }}<!> else <!TYPE_MISMATCH!>{{ <!CANNOT_INFER_PARAMETER_TYPE, EXPECTED_PARAMETERS_NUMBER_MISMATCH!>str<!> -> "this" }}<!>
+    val x6: String.() -> String = if (true) <!TYPE_MISMATCH!>{{ <!CANNOT_INFER_PARAMETER_TYPE, EXPECTED_PARAMETERS_NUMBER_MISMATCH!>str<!> -> "this" }}<!> else {{ "this" }}
+    val x7: String.() -> String = select({ -> this }, { -> this })
+    val x8: String.() -> String = select({ this }, { this })
+}

compiler/testData/diagnostics/tests/inference/extensionLambdasAndArrow.txt

@@ -0,0 +1,3 @@
+package
+
+public fun main(): kotlin.Unit

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

@@ -9953,6 +9953,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTestWithFirVali
                 runTest("compiler/testData/diagnostics/tests/inference/expectedTypeWithGenerics.kt");
             }
 
+            @TestMetadata("extensionLambdasAndArrow.kt")
+            public void testExtensionLambdasAndArrow() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inference/extensionLambdasAndArrow.kt");
+            }
+
             @TestMetadata("findViewById.kt")
             public void testFindViewById() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inference/findViewById.kt");

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

@@ -9948,6 +9948,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/inference/expectedTypeWithGenerics.kt");
             }
 
+            @TestMetadata("extensionLambdasAndArrow.kt")
+            public void testExtensionLambdasAndArrow() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inference/extensionLambdasAndArrow.kt");
+            }
+
             @TestMetadata("findViewById.kt")
             public void testFindViewById() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inference/findViewById.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -12845,6 +12845,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)
     public static class InlineClasses extends AbstractLightAnalysisModeTest {
+        @TestMetadata("anySuperCall.kt")
+        public void ignoreAnySuperCall() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/anySuperCall.kt");
+        }
+
         @TestMetadata("fieldNameClash.kt")
         public void ignoreFieldNameClash() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/fieldNameClash.kt");
@@ -12873,11 +12878,6 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/inlineClasses/annotatedMemberExtensionProperty.kt");
         }
 
-        @TestMetadata("anySuperCall.kt")
-        public void testAnySuperCall() throws Exception {
-            runTest("compiler/testData/codegen/box/inlineClasses/anySuperCall.kt");
-        }
-
         @TestMetadata("boundCallableReferencePassedToInlineFunction.kt")
         public void testBoundCallableReferencePassedToInlineFunction() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/boundCallableReferencePassedToInlineFunction.kt");