QmlJS: Improve support for multiple imports into same alias

Add extra handling for aliased imports to avoid handling
shadowed imports as unknown which in turn ignored them
and marked their members as unknown types and did not
provide auto completion for their members.

Fixes: QTCREATORBUG-15684
Change-Id: Iee1009cbdfde13ce261854c3239b9b50c434f563
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/libs/qmljs/qmljscontext.cpp

@@ -104,6 +104,9 @@ const Imports *Context::imports(const QmlJS::Document *doc) const
 const ObjectValue *Context::lookupType(const QmlJS::Document *doc, UiQualifiedId *qmlTypeName,
                                        UiQualifiedId *qmlTypeNameEnd) const
 {
+    if (!qmlTypeName)
+        return nullptr;
+
     const Imports *importsObj = imports(doc);
     if (!importsObj)
         return nullptr;
@@ -111,8 +114,13 @@ const ObjectValue *Context::lookupType(const QmlJS::Document *doc, UiQualifiedId
     if (!objectValue)
         return nullptr;
 
-    for (UiQualifiedId *iter = qmlTypeName; objectValue && iter && iter != qmlTypeNameEnd;
+    UiQualifiedId *iter = qmlTypeName;
-         iter = iter->next) {
+    if (const ObjectValue *value = importsObj->aliased(iter->name.toString())) {
+        objectValue = value;
+        iter = iter->next;
+    }
+
+    for ( ; objectValue && iter && iter != qmlTypeNameEnd; iter = iter->next) {
         const Value *value = objectValue->lookupMember(iter->name.toString(), this, nullptr, false);
         if (!value)
             return nullptr;
@@ -125,6 +133,9 @@ const ObjectValue *Context::lookupType(const QmlJS::Document *doc, UiQualifiedId
 
 const ObjectValue *Context::lookupType(const QmlJS::Document *doc, const QStringList &qmlTypeName) const
 {
+    if (qmlTypeName.isEmpty())
+        return nullptr;
+
     const Imports *importsObj = imports(doc);
     if (!importsObj)
         return nullptr;
@@ -132,11 +143,14 @@ const ObjectValue *Context::lookupType(const QmlJS::Document *doc, const QString
     if (!objectValue)
         return nullptr;
 
-    foreach (const QString &name, qmlTypeName) {
+    auto iter = qmlTypeName.cbegin();
-        if (!objectValue)
+    if (const ObjectValue *value = importsObj->aliased(*iter)) {
-            return nullptr;
+        objectValue = value;
-
+        ++iter;
-        const Value *value = objectValue->lookupMember(name, this);
+    }
+    auto end = qmlTypeName.cend();
+    for ( ; objectValue && iter != end; ) {
+        const Value *value = objectValue->lookupMember(*iter, this);
         if (!value)
             return nullptr;
 

src/libs/qmljs/qmljsinterpreter.cpp

@@ -2355,6 +2355,12 @@ TypeScope::TypeScope(const Imports *imports, ValueOwner *valueOwner)
 const Value *TypeScope::lookupMember(const QString &name, const Context *context,
                                            const ObjectValue **foundInObject, bool) const
 {
+    if (const ObjectValue *value = m_imports->resolveAliasAndMarkUsed(name)) {
+        if (foundInObject)
+            *foundInObject = this;
+        return value;
+    }
+
     const QList<Import> &imports = m_imports->all();
     for (int pos = imports.size(); --pos >= 0; ) {
         const Import &i = imports.at(pos);
@@ -2365,16 +2371,6 @@ const Value *TypeScope::lookupMember(const QString &name, const Context *context
         if (info.type() == ImportType::File || info.type() == ImportType::QrcFile)
             continue;
 
-        if (!info.as().isEmpty()) {
-            if (info.as() == name) {
-                if (foundInObject)
-                    *foundInObject = this;
-                i.used = true;  // FIXME: This evilly modifies a 'const' object
-                return import;
-            }
-            continue;
-        }
-
         if (const Value *v = import->lookupMember(name, context, foundInObject)) {
             i.used = true;
             return v;
@@ -2418,26 +2414,10 @@ JSImportScope::JSImportScope(const Imports *imports, ValueOwner *valueOwner)
 const Value *JSImportScope::lookupMember(const QString &name, const Context *,
                                          const ObjectValue **foundInObject, bool) const
 {
-    const QList<Import> &imports = m_imports->all();
+    const ObjectValue *value = m_imports->resolveAliasAndMarkUsed(name);
-    for (int pos = imports.size(); --pos >= 0; ) {
-        const Import &i = imports.at(pos);
-        const ObjectValue *import = i.object;
-        const ImportInfo &info = i.info;
-
-        // JS imports are always: import "somefile.js" as Foo
-        if (info.type() != ImportType::File && info.type() != ImportType::QrcFile)
-            continue;
-
-        if (info.as() == name) {
-            if (foundInObject)
-                *foundInObject = this;
-            i.used = true;
-            return import;
-        }
-    }
     if (foundInObject)
-        *foundInObject = nullptr;
+        *foundInObject = value ? this : nullptr;
-    return nullptr;
+    return value;
 }
 
 void JSImportScope::processMembers(MemberProcessor *processor) const
@@ -2464,10 +2444,31 @@ Imports::Imports(ValueOwner *valueOwner)
     , m_importFailed(false)
 {}
 
+class MemberCopy : public MemberProcessor
+{
+public:
+    explicit MemberCopy(ObjectValue *value) : m_value(value) {}
+    bool processProperty(const QString &name, const Value *value,
+                         const PropertyInfo & /*propertyInfo*/) override
+    {
+        m_value->setMember(name, value);
+        return true;
+    }
+private:
+    ObjectValue *m_value = nullptr;
+};
+
 void Imports::append(const Import &import)
 {
     // when doing lookup, imports with 'as' clause are looked at first
     if (!import.info.as().isEmpty()) {
+        const QString alias = import.info.as();
+        if (!m_aliased.contains(alias))
+            m_aliased.insert(alias, m_typeScope->valueOwner()->newObject(nullptr));
+        ObjectValue *obj = m_aliased[alias];
+        MemberCopy copyProcessor(obj);
+        import.object->processMembers(&copyProcessor);
+
         m_imports.append(import);
     } else {
         // find first as-import and prepend
@@ -2554,6 +2555,11 @@ const QList<Import> &Imports::all() const
     return m_imports;
 }
 
+const ObjectValue *Imports::aliased(const QString &name) const
+{
+    return m_aliased.value(name, nullptr);
+}
+
 const TypeScope *Imports::typeScope() const
 {
     return m_typeScope;
@@ -2564,6 +2570,20 @@ const JSImportScope *Imports::jsImportScope() const
     return m_jsImportScope;
 }
 
+const ObjectValue *Imports::resolveAliasAndMarkUsed(const QString &name) const
+{
+    if (const ObjectValue *value = m_aliased.value(name, nullptr)) {
+        // mark all respective ImportInfo objects to avoid dropping imports (QmlDesigner) on rewrite
+        for (const Import &i : qAsConst(m_imports)) {
+            const ImportInfo &info = i.info;
+            if (info.as() == name)
+                i.used = true; // FIXME: This evilly modifies a 'const' object
+        }
+        return value;
+    }
+    return nullptr;
+}
+
 #ifdef QT_DEBUG
 
 class MemberDumper: public MemberProcessor

src/libs/qmljs/qmljsinterpreter.h

@@ -1094,10 +1094,13 @@ public:
     bool importFailed() const;
 
     const QList<Import> &all() const;
+    const ObjectValue *aliased(const QString &name) const;
 
     const TypeScope *typeScope() const;
     const JSImportScope *jsImportScope() const;
 
+    const ObjectValue *resolveAliasAndMarkUsed(const QString &name) const;
+
 #ifdef QT_DEBUG
     void dump() const;
 #endif
@@ -1106,6 +1109,7 @@ private:
     // holds imports in the order they appeared,
     // lookup order is back to front
     QList<Import> m_imports;
+    QHash<QString, ObjectValue *> m_aliased;
     TypeScope *m_typeScope;
     JSImportScope *m_jsImportScope;
     bool m_importFailed;