From 177b0dc52550d7dad667903fa05978dad4ab960b Mon Sep 17 00:00:00 2001
From: furkanocalan <furkan.ocalan@huawei.com>
Date: Wed, 13 Aug 2025 16:46:39 +0300
Subject: [PATCH] Array literal assign to a union of FixedArray

Issue: #ICSU61
Description: There is a incorrect assignment in the array literal. Type checked for fixed array and warning message removed
Signed-off-by: furkanocalan <furkan.ocalan@huawei.com>
---
 ets2panda/checker/ETSAnalyzer.cpp | 73 +++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/ets2panda/checker/ETSAnalyzer.cpp b/ets2panda/checker/ETSAnalyzer.cpp
index 110ba4ec5c..767af7a73f 100644
--- a/ets2panda/checker/ETSAnalyzer.cpp
+++ b/ets2panda/checker/ETSAnalyzer.cpp
@@ -28,6 +28,7 @@
 #include "types/type.h"
 #include "checker/types/typeError.h"
 
+#include <iostream>
 #include <unordered_set>
 
 namespace ark::es2panda::checker {
@@ -973,6 +974,68 @@ static Type *GetAppropriatePreferredType(Type *originalType, std::function<bool(
     return preferredType;
 }
 
+static inline bool IsFixedArrayType(const Type *type)
+{
+    return type != nullptr && type->IsETSArrayType() && !type->IsETSResizableArrayType() && !type->IsETSTupleType();
+}
+
+static Type *SelectFixedArrayPreferredTypeForLiteral(ETSChecker *checker, ir::ArrayExpression *arrayLiteral,
+                                                     Type *contextualType)
+{
+    if (checker == nullptr || arrayLiteral == nullptr || contextualType == nullptr ||
+        !contextualType->IsETSUnionType()) {
+        return nullptr;
+    }
+
+    auto &unionAlternatives = contextualType->AsETSUnionType()->ConstituentTypes();
+
+    Type *chosenFixedArray = nullptr;
+    bool multipleDifferentMatches = false;
+
+    for (Type *candidate : unionAlternatives) {
+        if (!IsFixedArrayType(candidate)) {
+            continue;
+        }
+
+        Type *candidateElementType = candidate->AsETSArrayType()->ElementType();
+        if (candidateElementType == nullptr) {
+            continue;
+        }
+
+        bool allElementsAssignable = true;
+
+        for (auto *elementNode : arrayLiteral->Elements()) {
+            if (elementNode == nullptr || elementNode->IsSpreadElement()) {
+                allElementsAssignable = false;
+                break;
+            }
+
+            Type *elementType = elementNode->TsType();
+            if (elementType == nullptr) {
+                elementType = elementNode->Check(checker);
+            }
+
+            if (elementType == nullptr || !checker->Relation()->IsAssignableTo(elementType, candidateElementType)) {
+                allElementsAssignable = false;
+                break;
+            }
+        }
+
+        if (!allElementsAssignable) {
+            continue;
+        }
+
+        if (chosenFixedArray != nullptr && !checker->Relation()->IsIdenticalTo(chosenFixedArray, candidate)) {
+            multipleDifferentMatches = true;
+            break;
+        }
+
+        chosenFixedArray = candidate;
+    }
+
+    return (chosenFixedArray != nullptr && !multipleDifferentMatches) ? chosenFixedArray : nullptr;
+}
+
 checker::Type *ETSAnalyzer::Check(ir::ArrayExpression *expr) const
 {
     ETSChecker *checker = GetETSChecker();
@@ -982,6 +1045,16 @@ checker::Type *ETSAnalyzer::Check(ir::ArrayExpression *expr) const
 
     auto *preferredType = GetAppropriatePreferredType(expr->PreferredType(), &Type::IsAnyETSArrayOrTupleType);
 
+    if (preferredType == nullptr || preferredType->IsETSUnionType()) {
+        Type *contextualType = (preferredType != nullptr) ? preferredType : expr->PreferredType();
+        if (contextualType != nullptr && contextualType->IsETSUnionType()) {
+            if (Type *fixedArrayChoice = SelectFixedArrayPreferredTypeForLiteral(checker, expr, contextualType)) {
+                preferredType = fixedArrayChoice;
+                expr->SetPreferredType(preferredType);
+            }
+        }
+    }
+
     if (preferredType != nullptr && preferredType->IsETSReadonlyArrayType()) {
         const auto elementType = preferredType->AsETSObjectType()->TypeArguments().front();
         preferredType = checker->CreateETSResizableArrayType(elementType);
-- 
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