[FIR-IDE] Fix completion check for generic extensions

Generic candidate extensions are completed in partial mode
when there is not enough information for type parameter in return position.
Partial completion mode in single candidate resolver leads to unconditionally failing candidate.
Providing noExpectedType instead of null guarantees full completion.

idea/idea-completion/testData/basic/common/extensions/ParametrizedExpectedType.kt

@@ -0,0 +1,11 @@
+// FIR_COMPARISON
+class Generic<T>
+
+fun <A : String, B, C> Generic<A>.extension(arg: (A) -> B): B = TODO()
+
+fun test() {
+    val v = Generic<String>()
+    v.ext<caret>
+}
+
+// EXIST: extension

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JSBasicCompletionTestGenerated.java

@@ -1433,6 +1433,11 @@ public class JSBasicCompletionTestGenerated extends AbstractJSBasicCompletionTes
                 runTest("idea/idea-completion/testData/basic/common/extensions/NoMemberExtensionsFromCompanionObject.kt");
             }
 
+            @TestMetadata("ParametrizedExpectedType.kt")
+            public void testParametrizedExpectedType() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/extensions/ParametrizedExpectedType.kt");
+            }
+
             @TestMetadata("StarTypeArg.kt")
             public void testStarTypeArg() throws Exception {
                 runTest("idea/idea-completion/testData/basic/common/extensions/StarTypeArg.kt");

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JvmBasicCompletionTestGenerated.java

@@ -1433,6 +1433,11 @@ public class JvmBasicCompletionTestGenerated extends AbstractJvmBasicCompletionT
                 runTest("idea/idea-completion/testData/basic/common/extensions/NoMemberExtensionsFromCompanionObject.kt");
             }
 
+            @TestMetadata("ParametrizedExpectedType.kt")
+            public void testParametrizedExpectedType() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/extensions/ParametrizedExpectedType.kt");
+            }
+
             @TestMetadata("StarTypeArg.kt")
             public void testStarTypeArg() throws Exception {
                 runTest("idea/idea-completion/testData/basic/common/extensions/StarTypeArg.kt");

idea/idea-fir/tests/org/jetbrains/kotlin/idea/completion/HighLevelJvmBasicCompletionTestGenerated.java

@@ -1433,6 +1433,11 @@ public class HighLevelJvmBasicCompletionTestGenerated extends AbstractHighLevelJ
                 runTest("idea/idea-completion/testData/basic/common/extensions/NoMemberExtensionsFromCompanionObject.kt");
             }
 
+            @TestMetadata("ParametrizedExpectedType.kt")
+            public void testParametrizedExpectedType() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/extensions/ParametrizedExpectedType.kt");
+            }
+
             @TestMetadata("StarTypeArg.kt")
             public void testStarTypeArg() throws Exception {
                 runTest("idea/idea-completion/testData/basic/common/extensions/StarTypeArg.kt");

idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/resolver/SingleCandidateResolver.kt

@@ -90,7 +90,8 @@ class SingleCandidateResolver(
                 candidate = candidate
             )
         }
-        val completionResult = firCallCompleter.completeCall(fakeCall, resolutionParameters.expectedType)
+        val expectedType = resolutionParameters.expectedType ?: bodyResolveComponents.noExpectedType
+        val completionResult = firCallCompleter.completeCall(fakeCall, expectedType)
         return if (completionResult.callCompleted) {
             completionResult.result
         } else null