FIR checker: report LOCAL_VARIABLE_WITH_TYPE_PARAMETERS

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt

@@ -866,6 +866,8 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         }
         val ACCESSOR_FOR_DELEGATED_PROPERTY by error<KtPropertyAccessor>()
         val ABSTRACT_PROPERTY_IN_PRIMARY_CONSTRUCTOR_PARAMETERS by error<KtModifierListOwner>(PositioningStrategy.ABSTRACT_MODIFIER)
+        val LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING by warning<KtProperty>(PositioningStrategy.TYPE_PARAMETERS_LIST)
+        val LOCAL_VARIABLE_WITH_TYPE_PARAMETERS by error<KtProperty>(PositioningStrategy.TYPE_PARAMETERS_LIST)
     }
 
     val MPP_PROJECTS by object : DiagnosticGroup("Multi-platform projects") {

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -476,6 +476,8 @@ object FirErrors {
     val WRONG_GETTER_RETURN_TYPE by error2<KtTypeReference, ConeKotlinType, ConeKotlinType>()
     val ACCESSOR_FOR_DELEGATED_PROPERTY by error0<KtPropertyAccessor>()
     val ABSTRACT_PROPERTY_IN_PRIMARY_CONSTRUCTOR_PARAMETERS by error0<KtModifierListOwner>(SourceElementPositioningStrategies.ABSTRACT_MODIFIER)
+    val LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING by warning0<KtProperty>(SourceElementPositioningStrategies.TYPE_PARAMETERS_LIST)
+    val LOCAL_VARIABLE_WITH_TYPE_PARAMETERS by error0<KtProperty>(SourceElementPositioningStrategies.TYPE_PARAMETERS_LIST)
 
     // Multi-platform projects
     val EXPECTED_DECLARATION_WITH_BODY by error0<KtDeclaration>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/CommonDeclarationCheckers.kt

@@ -12,10 +12,7 @@ import org.jetbrains.kotlin.fir.analysis.cfa.FirReturnsImpliesAnalyzer
 import org.jetbrains.kotlin.fir.analysis.checkers.cfa.FirControlFlowChecker
 import org.jetbrains.kotlin.fir.analysis.checkers.declaration.*
 import org.jetbrains.kotlin.fir.analysis.checkers.expression.FirAnonymousFunctionParametersChecker
-import org.jetbrains.kotlin.fir.analysis.checkers.syntax.FirAnonymousFunctionSyntaxChecker
+import org.jetbrains.kotlin.fir.analysis.checkers.syntax.*
-import org.jetbrains.kotlin.fir.analysis.checkers.syntax.FirDelegationInInterfaceSyntaxChecker
-import org.jetbrains.kotlin.fir.analysis.checkers.syntax.FirFunctionTypeParametersSyntaxChecker
-import org.jetbrains.kotlin.fir.analysis.checkers.syntax.FirTypeParameterSyntaxChecker
 
 object CommonDeclarationCheckers : DeclarationCheckers() {
     override val basicDeclarationCheckers: Set<FirBasicDeclarationChecker>
@@ -59,6 +56,7 @@ object CommonDeclarationCheckers : DeclarationCheckers() {
             FirDelegatedPropertyChecker,
             FirInlinePropertyChecker,
             FirPropertyFromParameterChecker,
+            FirLocalVariableTypeParametersSyntaxChecker,
         )
 
     override val classCheckers: Set<FirClassChecker>

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/syntax/FirLocalVariableTypeParametersSyntaxChecker.kt

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2010-2021 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.fir.analysis.checkers.syntax
+
+import org.jetbrains.kotlin.config.LanguageFeature
+import org.jetbrains.kotlin.fir.FirFakeSourceElementKind
+import org.jetbrains.kotlin.fir.FirPsiSourceElement
+import org.jetbrains.kotlin.fir.FirSourceElement
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
+import org.jetbrains.kotlin.fir.analysis.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.analysis.diagnostics.typeParametersList
+import org.jetbrains.kotlin.fir.declarations.FirProperty
+import org.jetbrains.kotlin.fir.languageVersionSettings
+import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.psi.KtProperty
+
+// KtExpression is the appropriate PsiElement type; local variables are used in increments/decrements of dot-qualified expressions.
+object FirLocalVariableTypeParametersSyntaxChecker : FirDeclarationSyntaxChecker<FirProperty, KtExpression>() {
+    override fun isApplicable(element: FirProperty, source: FirSourceElement): Boolean =
+        source.kind !is FirFakeSourceElementKind && element.isLocal
+
+    override fun checkPsi(
+        element: FirProperty,
+        source: FirPsiSourceElement,
+        psi: KtExpression,
+        context: CheckerContext,
+        reporter: DiagnosticReporter
+    ) {
+        if (psi is KtProperty && psi.typeParameterList != null) {
+            val diagnostic =
+                if (context.session.languageVersionSettings.supportsFeature(LanguageFeature.ProhibitTypeParametersForLocalVariables))
+                    FirErrors.LOCAL_VARIABLE_WITH_TYPE_PARAMETERS else FirErrors.LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING
+            reporter.reportOn(source, diagnostic, context)
+        }
+    }
+
+    override fun checkLightTree(
+        element: FirProperty,
+        source: FirSourceElement,
+        context: CheckerContext,
+        reporter: DiagnosticReporter
+    ) {
+        source.treeStructure.typeParametersList(source.lighterASTNode)?.let { _ ->
+            val diagnostic =
+                if (context.session.languageVersionSettings.supportsFeature(LanguageFeature.ProhibitTypeParametersForLocalVariables))
+                    FirErrors.LOCAL_VARIABLE_WITH_TYPE_PARAMETERS else FirErrors.LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING
+            reporter.reportOn(source, diagnostic, context)
+
+        }
+    }
+}

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt

@@ -256,6 +256,8 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.LEAKED_IN_PLACE_L
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.LOCAL_ANNOTATION_CLASS_ERROR
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.LOCAL_INTERFACE_NOT_ALLOWED
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.LOCAL_OBJECT_NOT_ALLOWED
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.LOCAL_VARIABLE_WITH_TYPE_PARAMETERS
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MANY_CLASSES_IN_SUPERTYPE_LIST
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MANY_COMPANION_OBJECTS
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MANY_IMPL_MEMBER_NOT_IMPLEMENTED
@@ -1252,6 +1254,8 @@ class FirDefaultErrorMessages {
             )
             map.put(ACCESSOR_FOR_DELEGATED_PROPERTY, "Delegated property cannot have accessors with non-default implementations")
             map.put(ABSTRACT_PROPERTY_IN_PRIMARY_CONSTRUCTOR_PARAMETERS, "This property cannot be declared abstract")
+            map.put(LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING, "Type parameters for local variables are deprecated")
+            map.put(LOCAL_VARIABLE_WITH_TYPE_PARAMETERS, "Local variables are not allowed to have type parameters")
 
             map.put(CONST_VAL_NOT_TOP_LEVEL_OR_OBJECT, "Const 'val' are only allowed on top level or in objects")
             map.put(CONST_VAL_WITH_GETTER, "Const 'val' should not have a getter")

compiler/testData/diagnostics/tests/annotations/AnnotationsForPropertyTypeParameter.fir.kt

@@ -9,6 +9,6 @@ class SomeClass {
     val <<!WRONG_ANNOTATION_TARGET!>@A1<!> <!WRONG_ANNOTATION_TARGET!>@A2(3)<!> <!WRONG_ANNOTATION_TARGET!>@A2<!> <!WRONG_ANNOTATION_TARGET!>@A1(<!TOO_MANY_ARGUMENTS!>12<!>)<!> <!WRONG_ANNOTATION_TARGET!>@A2(<!ARGUMENT_TYPE_MISMATCH!>"Test"<!>)<!> T> T.field: Int get() = 12
 
     fun foo() {
-        val <@A1 @A2(3) @A2 @A1(12) @A2("Test") T> localVal = 12
+        val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><@A1 @A2(3) @A2 @A1(12) @A2("Test") T><!> localVal = 12
     }
 }

compiler/testData/diagnostics/tests/declarationChecks/localVariablesWithTypeParameters_1_3.fir.kt

@@ -4,13 +4,13 @@
 import kotlin.reflect.KProperty
 
 fun test() {
-    val <T> a0 = 0
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T><!> a0 = 0
-    val <T : __UNRESOLVED__> a1 = ""
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T : __UNRESOLVED__><!> a1 = ""
-    val <T : String> a2 = 0
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T : String><!> a2 = 0
-    <!WRONG_MODIFIER_TARGET!>const<!> val <T> a3 = 0
+    <!WRONG_MODIFIER_TARGET!>const<!> val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T><!> a3 = 0
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val <T> a4 = 0
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T><!> a4 = 0
-    val <T> a5 by Delegate<Int>()
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T><!> a5 by Delegate<Int>()
-    val <T> a6 by <!DELEGATE_SPECIAL_FUNCTION_NONE_APPLICABLE!>Delegate<<!UNRESOLVED_REFERENCE!>T<!>>()<!>
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING!><T><!> a6 by <!DELEGATE_SPECIAL_FUNCTION_NONE_APPLICABLE!>Delegate<<!UNRESOLVED_REFERENCE!>T<!>>()<!>
 }
 
 class Delegate<F> {

compiler/testData/diagnostics/tests/declarationChecks/localVariablesWithTypeParameters_1_4.fir.kt

@@ -4,13 +4,13 @@
 import kotlin.reflect.KProperty
 
 fun test() {
-    val <T> a0 = 0
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> a0 = 0
-    val <T : __UNRESOLVED__> a1 = ""
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T : __UNRESOLVED__><!> a1 = ""
-    val <T : String> a2 = 0
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T : String><!> a2 = 0
-    <!WRONG_MODIFIER_TARGET!>const<!> val <T> a3 = 0
+    <!WRONG_MODIFIER_TARGET!>const<!> val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> a3 = 0
-    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val <T> a4 = 0
+    <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit<!> val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> a4 = 0
-    val <T> a5 by Delegate<Int>()
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> a5 by Delegate<Int>()
-    val <T> a6 by <!DELEGATE_SPECIAL_FUNCTION_NONE_APPLICABLE!>Delegate<<!UNRESOLVED_REFERENCE!>T<!>>()<!>
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> a6 by <!DELEGATE_SPECIAL_FUNCTION_NONE_APPLICABLE!>Delegate<<!UNRESOLVED_REFERENCE!>T<!>>()<!>
 }
 
 class Delegate<F> {

compiler/tests-spec/testData/diagnostics/notLinked/local-variables/type-parameters/neg/1.fir.kt

@@ -3,32 +3,32 @@
 
 // TESTCASE NUMBER: 1
 fun case_1() {
-    val <T> x1 = 1
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> x1 = 1
-    var <T> x2 = 1
+    var <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> x2 = 1
 }
 
 // TESTCASE NUMBER: 2
 fun case_2() {
-    val <T> x1: Int = 1
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> x1: Int = 1
-    var <T> x2: Int = 1
+    var <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> x2: Int = 1
 }
 
 // TESTCASE NUMBER: 3
 fun case_3() {
-    val <T> x1: Map<Int, Int> = mapOf(1 to 1)
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> x1: Map<Int, Int> = mapOf(1 to 1)
-    var <T> x2: Map<Int, Int> = mapOf(1 to 1)
+    var <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> x2: Map<Int, Int> = mapOf(1 to 1)
 }
 
 // TESTCASE NUMBER: 4
 fun case_4() {
-    val <T> y1: Number where __UNRESOLVED__: __UNRESOLVED__ = 1
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> y1: Number where __UNRESOLVED__: __UNRESOLVED__ = 1
-    var <T> y2: Number where __UNRESOLVED__: __UNRESOLVED__ = 1
+    var <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> y2: Number where __UNRESOLVED__: __UNRESOLVED__ = 1
 }
 
 // TESTCASE NUMBER: 5
 fun case_5() {
-    val <T : __UNRESOLVED__> x1: Map<Int, Int> = mapOf(1 to 1)
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T : __UNRESOLVED__><!> x1: Map<Int, Int> = mapOf(1 to 1)
-    var <T : __UNRESOLVED__> x2: Map<Int, Int> = mapOf(1 to 1)
+    var <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T : __UNRESOLVED__><!> x2: Map<Int, Int> = mapOf(1 to 1)
 }
 
 /*
@@ -51,19 +51,19 @@ fun case_7() {
 
 // TESTCASE NUMBER: 8
 fun case_8() {
-    val <A, B : A, C : B, D : C, E : D> x1 = 1
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><A, B : A, C : B, D : C, E : D><!> x1 = 1
-    var <A, B : A, C : B, D : C, E : D> x2 = 2
+    var <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><A, B : A, C : B, D : C, E : D><!> x2 = 2
 }
 
 // TESTCASE NUMBER: 9
-fun case_9(y: Boolean?) = when (val <T> x = y) {
+fun case_9(y: Boolean?) = when (val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> x = y) {
     true -> null
     false -> null
     null -> null
 }
 
 // TESTCASE NUMBER: 10
-fun case_10(x: Boolean?) = when (val <T> x where T: suspend () -> Unit, T: Boolean = x) {
+fun case_10(x: Boolean?) = when (val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> x where T: suspend () -> Unit, T: Boolean = x) {
     true -> null
     false -> null
     null -> null
@@ -71,24 +71,24 @@ fun case_10(x: Boolean?) = when (val <T> x where T: suspend () -> Unit, T: Boole
 
 // TESTCASE NUMBER: 11
 fun case_11() {
-    val <T> x by lazy { 1 }
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> x by lazy { 1 }
-    var <T> x by <!DELEGATE_SPECIAL_FUNCTION_MISSING!>lazy { 1 }<!>
+    var <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T><!> x by <!DELEGATE_SPECIAL_FUNCTION_MISSING!>lazy { 1 }<!>
 }
 
 // TESTCASE NUMBER: 12
 fun case_12() {
-    val <T : __UNRESOLVED__> x: Int
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T : __UNRESOLVED__><!> x: Int
-    var <T : __UNRESOLVED__> x: Int
+    var <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T : __UNRESOLVED__><!> x: Int
 }
 
 // TESTCASE NUMBER: 13
 fun case_13() {
-    val <T : __UNRESOLVED__> x: Int where __UNRESOLVED__: __UNRESOLVED__
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T : __UNRESOLVED__><!> x: Int where __UNRESOLVED__: __UNRESOLVED__
-    var <T : __UNRESOLVED__> x: Int where __UNRESOLVED__: __UNRESOLVED__
+    var <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T : __UNRESOLVED__><!> x: Int where __UNRESOLVED__: __UNRESOLVED__
 }
 
 // TESTCASE NUMBER: 14
 fun case_14() {
-    val <T : T> x1 = 1
+    val <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T : T><!> x1 = 1
-    var <T : T> x2 = 1
+    var <!LOCAL_VARIABLE_WITH_TYPE_PARAMETERS!><T : T><!> x2 = 1
 }

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDataClassConverters.kt

@@ -2385,6 +2385,18 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.LOCAL_VARIABLE_WITH_TYPE_PARAMETERS_WARNING) { firDiagnostic ->
+        LocalVariableWithTypeParametersWarningImpl(
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
+    add(FirErrors.LOCAL_VARIABLE_WITH_TYPE_PARAMETERS) { firDiagnostic ->
+        LocalVariableWithTypeParametersImpl(
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.EXPECTED_DECLARATION_WITH_BODY) { firDiagnostic ->
         ExpectedDeclarationWithBodyImpl(
             firDiagnostic as FirPsiDiagnostic,

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnostics.kt

@@ -1686,6 +1686,14 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         override val diagnosticClass get() = AbstractPropertyInPrimaryConstructorParameters::class
     }
 
+    abstract class LocalVariableWithTypeParametersWarning : KtFirDiagnostic<KtProperty>() {
+        override val diagnosticClass get() = LocalVariableWithTypeParametersWarning::class
+    }
+
+    abstract class LocalVariableWithTypeParameters : KtFirDiagnostic<KtProperty>() {
+        override val diagnosticClass get() = LocalVariableWithTypeParameters::class
+    }
+
     abstract class ExpectedDeclarationWithBody : KtFirDiagnostic<KtDeclaration>() {
         override val diagnosticClass get() = ExpectedDeclarationWithBody::class
     }

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnosticsImpl.kt

@@ -2713,6 +2713,20 @@ internal class AbstractPropertyInPrimaryConstructorParametersImpl(
     override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
 }
 
+internal class LocalVariableWithTypeParametersWarningImpl(
+    firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.LocalVariableWithTypeParametersWarning(), KtAbstractFirDiagnostic<KtProperty> {
+    override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
+}
+
+internal class LocalVariableWithTypeParametersImpl(
+    firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.LocalVariableWithTypeParameters(), KtAbstractFirDiagnostic<KtProperty> {
+    override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
+}
+
 internal class ExpectedDeclarationWithBodyImpl(
     firDiagnostic: FirPsiDiagnostic,
     override val token: ValidityToken,