[HL API] Fix FE10 implementation of KtExpressionTypeProvider

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

@@ -35,7 +35,11 @@ public interface KtExpressionTypeProviderMixIn : KtAnalysisSessionMixIn {
         withValidityAssertion { analysisSession.expressionTypeProvider.getKtExpressionType(this) }
 
     /**
-     * Returns the return type of the given [KtDeclaration] as [KtType]
+     * Returns the return type of the given [KtDeclaration] as [KtType].
+     *
+     * IMPORTANT: For `vararg foo: T` parameter returns full `Array<out T>` type (unlike
+     * [KtValueParameterSymbol.returnType][org.jetbrains.kotlin.analysis.api.symbols.KtValueParameterSymbol.returnType],
+     * which returns `T`).
      */
     public fun KtDeclaration.getReturnKtType(): KtType =
         withValidityAssertion { analysisSession.expressionTypeProvider.getReturnTypeForKtDeclaration(this) }

analysis/analysis-api/testData/components/expressionTypeProvider/declarationReturnType/varargParam.kt

@@ -0,0 +1,5 @@
+class Foo(vararg constructorValues: String)
+
+fun test(vararg values: String) {}
+
+fun test(vararg primitiveValues: Int) {}

analysis/analysis-api/testData/components/expressionTypeProvider/declarationReturnType/varargParam.txt

@@ -0,0 +1,7 @@
+Foo@(1,1)
+  Foo@(1,10) : Foo
+    constructorValues@(1,11) : kotlin.Array<out kotlin.String>
+test@(3,1) : kotlin.Unit
+  values@(3,10) : kotlin.Array<out kotlin.String>
+test@(5,1) : kotlin.Unit
+  primitiveValues@(5,10) : kotlin.IntArray