[NI] Fix exception, recorded type for function statement can be null

See `checkStatementType`, we return `null` to reduce count of errors.

 Also, note that named function which is used as last statement in lambda
 doesn't coerce to Unit, this is a separate bug and will be addressed later,
 see #KT-25383

 #EA-121026 Fixed

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tower/ResolvedAtomCompleter.kt

@@ -15,6 +15,7 @@ import org.jetbrains.kotlin.descriptors.impl.FunctionDescriptorImpl
 import org.jetbrains.kotlin.descriptors.impl.ReceiverParameterDescriptorImpl
 import org.jetbrains.kotlin.psi.KtElement
 import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.psi.KtNamedFunction
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.BindingTrace
 import org.jetbrains.kotlin.resolve.DeprecationResolver
@@ -139,7 +140,12 @@ class ResolvedAtomCompleter(
                 ?: throw AssertionError("No function descriptor for resolved lambda argument")
         functionDescriptor.setReturnType(returnType)
 
-        val existingLambdaType = trace.getType(ktArgumentExpression) ?: throw AssertionError("No type for resolved lambda argument")
+        val existingLambdaType = trace.getType(ktArgumentExpression)
+        if (existingLambdaType == null) {
+            if (ktFunction is KtNamedFunction && ktFunction.nameIdentifier != null) return // it's a statement
+
+            throw AssertionError("No type for resolved lambda argument: ${ktArgumentExpression.text}")
+        }
         val substitutedFunctionalType = createFunctionType(
             builtIns,
             existingLambdaType.annotations,

compiler/testData/diagnostics/tests/declarationChecks/namedFunAsLastExpressionInBlock.kt

@@ -27,15 +27,15 @@ fun test() {
     <!SYNTAX!><!>fun named7() = 1
 
     val x3 = when (1) {
-        0 -> <!OI;EXPECTED_TYPE_MISMATCH!>fun <!NI;ANONYMOUS_FUNCTION_WITH_NAME!>named8<!>(): Int {return 1}<!>
+        0 -> <!EXPECTED_TYPE_MISMATCH!>fun named8(): Int {return 1}<!>
-        else -> <!OI;EXPECTED_TYPE_MISMATCH!>fun <!NI;ANONYMOUS_FUNCTION_WITH_NAME!>named9<!>() = 1<!>
+        else -> <!EXPECTED_TYPE_MISMATCH!>fun named9() = 1<!>
     }
 
     val x31 = when (1) {
         0 -> {
-            <!OI;EXPECTED_TYPE_MISMATCH!>fun <!NI;ANONYMOUS_FUNCTION_WITH_NAME!>named10<!>(): Int {return 1}<!>
+            <!EXPECTED_TYPE_MISMATCH!>fun named10(): Int {return 1}<!>
         }
-        else -> <!OI;EXPECTED_TYPE_MISMATCH!>fun <!NI;ANONYMOUS_FUNCTION_WITH_NAME!>named11<!>() = 1<!>
+        else -> <!EXPECTED_TYPE_MISMATCH!>fun named11() = 1<!>
     }
 
     val x4 = {
@@ -55,5 +55,5 @@ fun success() {
     run2 { fun named2() = 1 }
 
     val x = run { fun named3() = 1 }
-    x checkType { _<Unit>() }
+    x checkType { <!NI;DEBUG_INFO_UNRESOLVED_WITH_TARGET, NI;UNRESOLVED_REFERENCE_WRONG_RECEIVER!>_<!><Unit>() }
 }

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

@@ -0,0 +1,10 @@
+// !LANGUAGE: +NewInference
+
+fun bar() {
+    if (true) <!TYPE_MISMATCH!>{
+        <!EXPECTED_TYPE_MISMATCH!>fun local() {
+        }<!>
+    }<!> else {
+
+    }
+}

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

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

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

@@ -9385,6 +9385,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 runTest("compiler/testData/diagnostics/tests/inference/listConstructor.kt");
             }
 
+            @TestMetadata("localFunctionInsideIfBlock.kt")
+            public void testLocalFunctionInsideIfBlock() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inference/localFunctionInsideIfBlock.kt");
+            }
+
             @TestMetadata("mapFunction.kt")
             public void testMapFunction() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inference/mapFunction.kt");

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

@@ -9385,6 +9385,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/inference/listConstructor.kt");
             }
 
+            @TestMetadata("localFunctionInsideIfBlock.kt")
+            public void testLocalFunctionInsideIfBlock() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inference/localFunctionInsideIfBlock.kt");
+            }
+
             @TestMetadata("mapFunction.kt")
             public void testMapFunction() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inference/mapFunction.kt");