diff --git a/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java b/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java
index 41abfdef487..791b1c2c8ec 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java
@@ -497,6 +497,11 @@ public interface Errors {
     DiagnosticFactory0<KtParameter> PLATFORM_CLASS_CONSTRUCTOR_PROPERTY_PARAMETER = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<KtExpression> PLATFORM_PROPERTY_INITIALIZER = DiagnosticFactory0.create(ERROR);
 
+    DiagnosticFactory0<KtTypeAlias> IMPL_TYPE_ALIAS_NOT_TO_CLASS = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);
+    DiagnosticFactory0<KtTypeAlias> IMPL_TYPE_ALIAS_TO_CLASS_WITH_DECLARATION_SITE_VARIANCE = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);
+    DiagnosticFactory0<KtTypeAlias> IMPL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);
+    DiagnosticFactory0<KtTypeAlias> IMPL_TYPE_ALIAS_WITH_COMPLEX_SUBSTITUTION = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);
+
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
     // Errors/warnings inside code blocks
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java b/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java
index 33919798b4c..0042210e2dc 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java
@@ -263,6 +263,11 @@ public class DefaultErrorMessages {
         MAP.put(PLATFORM_CLASS_CONSTRUCTOR_PROPERTY_PARAMETER, "Platform class constructor cannot have a property parameter");
         MAP.put(PLATFORM_PROPERTY_INITIALIZER, "Platform property cannot have an initializer");
 
+        MAP.put(IMPL_TYPE_ALIAS_NOT_TO_CLASS, "Right-hand side of 'impl' type alias should be a class, not another type alias");
+        MAP.put(IMPL_TYPE_ALIAS_TO_CLASS_WITH_DECLARATION_SITE_VARIANCE, "Aliased class should not have type parameters with declaration-site variance");
+        MAP.put(IMPL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE, "Right-hand side of 'impl' type alias cannot contain use-site variance or star projections");
+        MAP.put(IMPL_TYPE_ALIAS_WITH_COMPLEX_SUBSTITUTION, "Type arguments in the right-hand side of 'impl' type alias should be its type parameters in the same order, e.g. 'impl typealias Foo<A, B> = Bar<A, B>'");
+
         MAP.put(PROJECTION_ON_NON_CLASS_TYPE_ARGUMENT, "Projections are not allowed on type arguments of functions and properties");
         MAP.put(SUPERTYPE_NOT_INITIALIZED, "This type has a constructor, and thus must be initialized here");
         MAP.put(NOTHING_TO_OVERRIDE, "''{0}'' overrides nothing", NAME);
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.kt
index 689a0702eb2..dbd8089df55 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.kt
@@ -181,6 +181,35 @@ class DeclarationsChecker(
                 trace.report(UNUSED_TYPEALIAS_PARAMETER.on(source, typeParameter, expandedType))
             }
         }
+
+        if (declaration.hasModifier(KtTokens.IMPL_KEYWORD)) {
+            checkImplTypeAlias(declaration, typeAliasDescriptor)
+        }
+    }
+
+    private fun checkImplTypeAlias(declaration: KtTypeAlias, typeAliasDescriptor: TypeAliasDescriptor) {
+        val rhs = typeAliasDescriptor.underlyingType
+        val classDescriptor = rhs.constructor.declarationDescriptor
+        if (classDescriptor !is ClassDescriptor) {
+            trace.report(IMPL_TYPE_ALIAS_NOT_TO_CLASS.on(declaration))
+            return
+        }
+
+        if (classDescriptor.declaredTypeParameters.any { it.variance != Variance.INVARIANT }) {
+            trace.report(IMPL_TYPE_ALIAS_TO_CLASS_WITH_DECLARATION_SITE_VARIANCE.on(declaration))
+            return
+        }
+
+        if (rhs.arguments.any { it.projectionKind != Variance.INVARIANT || it.isStarProjection }) {
+            trace.report(IMPL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE.on(declaration))
+            return
+        }
+
+        if (rhs.arguments.map { it.type.constructor.declarationDescriptor as? TypeParameterDescriptor } !=
+                typeAliasDescriptor.declaredTypeParameters) {
+            trace.report(IMPL_TYPE_ALIAS_WITH_COMPLEX_SUBSTITUTION.on(declaration))
+            return
+        }
     }
 
     private fun getUsedTypeAliasParameters(type: KotlinType, typeAlias: TypeAliasDescriptor): Set<TypeParameterDescriptor> =
diff --git a/compiler/testData/diagnostics/tests/multiplatform/platformClass/genericClassImplTypeAlias.kt b/compiler/testData/diagnostics/tests/multiplatform/platformClass/genericClassImplTypeAlias.kt
new file mode 100644
index 00000000000..1c72d1d2773
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/multiplatform/platformClass/genericClassImplTypeAlias.kt
@@ -0,0 +1,30 @@
+// !LANGUAGE: +MultiPlatformProjects
+// MODULE: m1-common
+// FILE: common.kt
+
+platform class C1
+platform class C2<A>
+platform class C3<B>
+platform class C4<D, E>
+platform class C5<F, G>
+platform class C6<H>
+platform class C7<I>
+platform class C8<J>
+platform class C9<K>
+platform class C10<L>
+
+// MODULE: m2-jvm(m1-common)
+// FILE: jvm.kt
+
+impl typealias C1 = String
+<!IMPL_TYPE_ALIAS_TO_CLASS_WITH_DECLARATION_SITE_VARIANCE!>impl typealias C2<<!UNUSED_TYPEALIAS_PARAMETER!>A<!>> = List<String><!>
+<!IMPL_TYPE_ALIAS_TO_CLASS_WITH_DECLARATION_SITE_VARIANCE!>impl typealias C3<B> = List<B><!>
+impl typealias C4<D, E> = MutableMap<D, E>
+<!IMPL_TYPE_ALIAS_WITH_COMPLEX_SUBSTITUTION!>impl typealias C5<F, G> = MutableMap<G, F><!>
+impl typealias C6<H> = MutableList<H>
+<!IMPL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE!>impl typealias C7<I> = MutableList<out I><!>
+<!IMPL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE!>impl typealias C8<<!UNUSED_TYPEALIAS_PARAMETER!>J<!>> = MutableList<*><!>
+<!IMPL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE!>impl typealias C9<K> = MutableList<in K><!>
+
+typealias Tmp<K> = MutableList<K>
+<!IMPL_TYPE_ALIAS_NOT_TO_CLASS!>impl typealias C10<L> = Tmp<L><!>
diff --git a/compiler/testData/diagnostics/tests/multiplatform/platformClass/genericClassImplTypeAlias.txt b/compiler/testData/diagnostics/tests/multiplatform/platformClass/genericClassImplTypeAlias.txt
new file mode 100644
index 00000000000..27b5a72d384
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/multiplatform/platformClass/genericClassImplTypeAlias.txt
@@ -0,0 +1,88 @@
+// -- Module: <m1-common> --
+package
+
+public final platform class C1 {
+    public constructor C1()
+    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 final platform class C10</*0*/ L> {
+    public constructor C10</*0*/ L>()
+    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 final platform class C2</*0*/ A> {
+    public constructor C2</*0*/ A>()
+    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 final platform class C3</*0*/ B> {
+    public constructor C3</*0*/ B>()
+    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 final platform class C4</*0*/ D, /*1*/ E> {
+    public constructor C4</*0*/ D, /*1*/ E>()
+    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 final platform class C5</*0*/ F, /*1*/ G> {
+    public constructor C5</*0*/ F, /*1*/ G>()
+    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 final platform class C6</*0*/ H> {
+    public constructor C6</*0*/ H>()
+    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 final platform class C7</*0*/ I> {
+    public constructor C7</*0*/ I>()
+    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 final platform class C8</*0*/ J> {
+    public constructor C8</*0*/ J>()
+    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 final platform class C9</*0*/ K> {
+    public constructor C9</*0*/ K>()
+    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
+}
+
+
+// -- Module: <m2-jvm> --
+package
+
+public typealias C1 = kotlin.String
+public typealias C10</*0*/ L>  = Tmp<L>
+public typealias C2</*0*/ A>  = kotlin.collections.List<kotlin.String>
+public typealias C3</*0*/ B>  = kotlin.collections.List<B>
+public typealias C4</*0*/ D, /*1*/ E>  = kotlin.collections.MutableMap<D, E>
+public typealias C5</*0*/ F, /*1*/ G>  = kotlin.collections.MutableMap<G, F>
+public typealias C6</*0*/ H>  = kotlin.collections.MutableList<H>
+public typealias C7</*0*/ I>  = kotlin.collections.MutableList<out I>
+public typealias C8</*0*/ J>  = kotlin.collections.MutableList<*>
+public typealias C9</*0*/ K>  = kotlin.collections.MutableList<in K>
+public typealias Tmp</*0*/ K>  = kotlin.collections.MutableList<K>
diff --git a/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java
index bd5d7180074..0f020d7fc4d 100644
--- a/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java
@@ -12576,6 +12576,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                     doTest(fileName);
                 }
 
+                @TestMetadata("genericClassImplTypeAlias.kt")
+                public void testGenericClassImplTypeAlias() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/multiplatform/platformClass/genericClassImplTypeAlias.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("platformClassMember.kt")
                 public void testPlatformClassMember() throws Exception {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/multiplatform/platformClass/platformClassMember.kt");