[AA] KtExpressionInfoProvider.getMissingCases: fix no subject case

return missing else branch (even if it's present, see kdoc)

^ KT-62875 fixed

analysis/analysis-api/src/org/jetbrains/kotlin/analysis/api/components/KtExpressionInfoProvider.kt

@@ -36,6 +36,15 @@ public interface KtExpressionInfoProviderMixIn : KtAnalysisSessionMixIn {
      *   else -> 3
      * }
      *
+     * If when-expression has no subject, then else-branch would be reported as missing even if it is explicitly present:
+     *
+     * fun test() {
+     *     when {
+     *         true -> {}
+     *         else -> {}
+     *     }
+     * }
+     *
      * Note that this function returns the same missing cases regardless of the existence of the else branch.
      * If you have to assume that it does not have the missing cases when it has an else branch,
      * you need a separate check whether it has an else branch or not.

analysis/analysis-api/testData/components/expressionInfoProvider/whenMissingCases/boolean_noSubject.kt

@@ -0,0 +1,5 @@
+fun test() {
+    <caret>when {
+        true -> {}
+    }
+}

analysis/analysis-api/testData/components/expressionInfoProvider/whenMissingCases/boolean_noSubject.txt

@@ -0,0 +1 @@
+Unknown - else

analysis/analysis-api/testData/components/expressionInfoProvider/whenMissingCases/boolean_noSubjectIncorrectCode.kt

@@ -0,0 +1,5 @@
+fun test() {
+    <caret>when() {
+        true -> {}
+    }
+}

analysis/analysis-api/testData/components/expressionInfoProvider/whenMissingCases/boolean_noSubjectIncorrectCode.txt

@@ -0,0 +1 @@
+Unknown - else

analysis/analysis-api/testData/components/expressionInfoProvider/whenMissingCases/boolean_noSubject_else.kt

@@ -0,0 +1,6 @@
+fun test() {
+    <caret>when {
+        true -> {}
+        else -> { }
+    }
+}

analysis/analysis-api/testData/components/expressionInfoProvider/whenMissingCases/boolean_noSubject_else.txt

@@ -0,0 +1 @@
+Unknown - else