Lambda in position with suspend function expected type:

simple case - val initializer.

compiler/frontend/src/org/jetbrains/kotlin/types/expressions/FunctionsTypingVisitor.kt

@@ -20,7 +20,7 @@ import com.google.common.collect.Lists
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.builtins.createFunctionType
 import org.jetbrains.kotlin.builtins.getReturnTypeFromFunctionType
-import org.jetbrains.kotlin.builtins.isFunctionType
+import org.jetbrains.kotlin.builtins.isBuiltinFunctionalType
 import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor
 import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
@@ -126,14 +126,15 @@ internal class FunctionsTypingVisitor(facade: ExpressionTypingInternals) : Expre
         }
     }
 
-    private fun SimpleFunctionDescriptor.createFunctionType(): KotlinType? {
+    private fun SimpleFunctionDescriptor.createFunctionType(suspendFunction: Boolean = false): KotlinType? {
         return createFunctionType(
                 components.builtIns,
                 Annotations.EMPTY,
                 extensionReceiverParameter?.type,
                 valueParameters.map { it.type },
                 null,
-                returnType ?: return null
+                returnType ?: return null,
+                suspendFunction = suspendFunction
         )
     }
 
@@ -141,7 +142,8 @@ internal class FunctionsTypingVisitor(facade: ExpressionTypingInternals) : Expre
         if (!expression.functionLiteral.hasBody()) return null
 
         val expectedType = context.expectedType
-        val functionTypeExpected = !noExpectedType(expectedType) && expectedType.isFunctionType
+        val functionTypeExpected = !noExpectedType(expectedType) && expectedType.isBuiltinFunctionalType
+        val suspendFunctionTypeExpected = !noExpectedType(expectedType) && expectedType.isSuspendFunctionType
 
         val functionDescriptor = createFunctionLiteralDescriptor(expression, context)
         expression.valueParameters.forEach {
@@ -151,7 +153,7 @@ internal class FunctionsTypingVisitor(facade: ExpressionTypingInternals) : Expre
         val safeReturnType = computeReturnType(expression, context, functionDescriptor, functionTypeExpected)
         functionDescriptor.setReturnType(safeReturnType)
 
-        val resultType = functionDescriptor.createFunctionType()!!
+        val resultType = functionDescriptor.createFunctionType(suspendFunctionTypeExpected)!!
         if (functionTypeExpected) {
             // all checks were done before
             return createTypeInfo(resultType, context)

compiler/testData/diagnostics/tests/coroutines/suspendFunctionType/lambdaInOverriddenValInitializer.kt

@@ -0,0 +1,23 @@
+interface Foo {
+    val foo: suspend () -> Unit
+}
+
+interface Bar<T> {
+    val bar: T
+}
+
+class Test1 : Foo {
+    override val <!PROPERTY_TYPE_MISMATCH_ON_OVERRIDE!>foo<!> = {}
+}
+
+class Test2 : Foo {
+    override val foo: suspend () -> Unit = {}
+}
+
+class Test3 : Bar<suspend () -> Unit> {
+    override val <!PROPERTY_TYPE_MISMATCH_ON_OVERRIDE!>bar<!> = {}
+}
+
+class Test4 : Bar<suspend () -> Unit> {
+    override val bar: suspend () -> Unit = {}
+}

compiler/testData/diagnostics/tests/coroutines/suspendFunctionType/lambdaInOverriddenValInitializer.txt

@@ -0,0 +1,47 @@
+package
+
+public interface Bar</*0*/ T> {
+    public abstract val bar: T
+    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 interface Foo {
+    public abstract val foo: suspend () -> kotlin.Unit
+    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 class Test1 : Foo {
+    public constructor Test1()
+    public open override /*1*/ val foo: () -> kotlin.Unit
+    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 class Test2 : Foo {
+    public constructor Test2()
+    public open override /*1*/ val foo: suspend () -> kotlin.Unit
+    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 class Test3 : Bar<suspend () -> kotlin.Unit> {
+    public constructor Test3()
+    public open override /*1*/ val bar: () -> kotlin.Unit
+    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 class Test4 : Bar<suspend () -> kotlin.Unit> {
+    public constructor Test4()
+    public open override /*1*/ val bar: suspend () -> kotlin.Unit
+    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
+}

compiler/testData/diagnostics/tests/coroutines/suspendFunctionType/lambdaInValInitializer.kt

@@ -0,0 +1,6 @@
+typealias SuspendFn = suspend () -> Unit
+
+val test1: suspend () -> Unit = {}
+val test2: suspend Any.() -> Unit = {}
+val test3: suspend Any.(Int) -> Int = { k: Int -> k + 1 }
+val test4: SuspendFn = {}

compiler/testData/diagnostics/tests/coroutines/suspendFunctionType/lambdaInValInitializer.txt

@@ -0,0 +1,7 @@
+package
+
+public val test1: suspend () -> kotlin.Unit
+public val test2: suspend kotlin.Any.() -> kotlin.Unit
+public val test3: suspend kotlin.Any.(kotlin.Int) -> kotlin.Int
+public val test4: SuspendFn /* = suspend () -> kotlin.Unit */
+public typealias SuspendFn = suspend () -> kotlin.Unit