Receiver of a safe call is not null inside the call also for extension functions + a pair of tests #KT-9033 Fixed

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/context/CallCandidateResolutionContext.java

@@ -75,7 +75,6 @@ public final class CallCandidateResolutionContext<D extends CallableDescriptor>
             @NotNull TracingStrategy tracing, @NotNull Call call, @NotNull ReceiverValue explicitExtensionReceiverForInvoke,
             @NotNull CandidateResolveMode candidateResolveMode
     ) {
-        candidateCall.getDataFlowInfoForArguments().setInitialDataFlowInfo(context.dataFlowInfo);
         return new CallCandidateResolutionContext<D>(
                 candidateCall, tracing, trace, context.scope, call, context.expectedType,
                 context.dataFlowInfo, context.contextDependency, context.checkArguments,

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/model/DataFlowInfoForArgumentsImpl.java

@@ -86,8 +86,8 @@ public class DataFlowInfoForArgumentsImpl implements MutableDataFlowInfoForArgum
     @NotNull
     @Override
     public DataFlowInfo getResultInfo() {
-        if (resultInfo == null) return initialInfo;
         assert initialInfo != null : "Initial data flow info was not set for call: " + call;
+        if (resultInfo == null) return initialInfo;
         return initialInfo.and(resultInfo);
     }
 }

compiler/testData/diagnostics/tests/smartCasts/safecalls/extensionCall.kt

@@ -0,0 +1,6 @@
+fun String.bar(s: String) = s
+
+fun foo(s: String?) {
+    s?.bar(<!DEBUG_INFO_SMARTCAST!>s<!>)
+    s?.charAt(<!DEBUG_INFO_SMARTCAST!>s<!>.length())
+}

compiler/testData/diagnostics/tests/smartCasts/safecalls/extensionCall.txt

@@ -0,0 +1,4 @@
+package
+
+public fun foo(/*0*/ s: kotlin.String?): kotlin.Unit
+public fun kotlin.String.bar(/*0*/ s: kotlin.String): kotlin.String

compiler/testData/diagnostics/testsWithStdLib/smartcasts/letUsesOwnReceiver.kt

@@ -0,0 +1,7 @@
+// Based on KT-9033
+fun f(s: String) = s
+
+fun foo(s: String?) {
+    s?.let { f(<!DEBUG_INFO_SMARTCAST!>s<!>) }
+    s?.let { f(it) }
+}

compiler/testData/diagnostics/testsWithStdLib/smartcasts/letUsesOwnReceiver.txt

@@ -0,0 +1,4 @@
+package
+
+public fun f(/*0*/ s: kotlin.String): kotlin.String
+public fun foo(/*0*/ s: kotlin.String?): kotlin.Unit

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

@@ -13895,6 +13895,12 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                     doTest(fileName);
                 }
 
+                @TestMetadata("extensionCall.kt")
+                public void testExtensionCall() throws Exception {
+                    String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/smartCasts/safecalls/extensionCall.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("falseArgument.kt")
                 public void testFalseArgument() throws Exception {
                     String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/smartCasts/safecalls/falseArgument.kt");

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

@@ -830,6 +830,21 @@ public class JetDiagnosticsTestWithStdLibGenerated extends AbstractJetDiagnostic
         }
     }
 
+    @TestMetadata("compiler/testData/diagnostics/testsWithStdLib/smartcasts")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class Smartcasts extends AbstractJetDiagnosticsTestWithStdLib {
+        public void testAllFilesPresentInSmartcasts() throws Exception {
+            JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/diagnostics/testsWithStdLib/smartcasts"), Pattern.compile("^(.+)\\.kt$"), true);
+        }
+
+        @TestMetadata("letUsesOwnReceiver.kt")
+        public void testLetUsesOwnReceiver() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/testsWithStdLib/smartcasts/letUsesOwnReceiver.kt");
+            doTest(fileName);
+        }
+    }
+
     @TestMetadata("compiler/testData/diagnostics/testsWithStdLib/varargs")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)