[Analysis API] Generify 'KtCodeFragmentModule' to support ordinary files

This commit introduces dangling file modules, which may be either
code fragments or ordinary Kotlin files. As before, code fragments are
analyzed against some context element, however ordinary files only
have a context module.

Code fragments can also have a dangling file module as a contextual one,
including other code fragment. This is done to support potential usages
in completion, intentions and refactorings.

analysis/project-structure/src/org/jetbrains/kotlin/analysis/project/structure/KtModule.kt

@@ -10,7 +10,6 @@ import com.intellij.psi.PsiFile
 import com.intellij.psi.search.GlobalSearchScope
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.platform.TargetPlatform
-import org.jetbrains.kotlin.psi.KtCodeFragment
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.resolve.PlatformDependentAnalyzerServices
 import java.nio.file.Path
@@ -216,21 +215,29 @@ public interface KtScriptDependencyModule : KtModule {
 }
 
 /**
- * A module for a Kotlin code fragment – a piece of code analyzed against a specific context element.
+ * A module for a dangling file. Such files are usually temporary and are stored in-memory.
+ * Dangling files may be created for various purposes, such as: a code fragment for the evaluator, a sandbox for testing code modification
+ * applicability, etc.
  */
-public interface KtCodeFragmentModule : KtModule {
+public interface KtDanglingFileModule : KtModule {
     /**
-     * A code fragment PSI.
+     * A temporary file PSI.
      */
-    public val codeFragment: KtCodeFragment
+    public val file: KtFile
 
     /**
-     * Module of the context element.
+     * The module against which the [file] is analyzed.
      */
     public val contextModule: KtModule
 
+    /**
+     * True if the [file] is a code fragment.
+     * Useful to recognize code fragments when their PSI was collected.
+     */
+    public val isCodeFragment: Boolean
+
     override val moduleDescription: String
-        get() = "Code fragment"
+        get() = "Temporary file"
 }
 
 /**

analysis/project-structure/src/org/jetbrains/kotlin/analysis/project/structure/impl/KtDanglingFileModuleImpl.kt

@@ -7,22 +7,35 @@ package org.jetbrains.kotlin.analysis.project.structure.impl
 
 import com.intellij.openapi.project.Project
 import com.intellij.psi.search.GlobalSearchScope
-import org.jetbrains.kotlin.analysis.project.structure.KtCodeFragmentModule
 import org.jetbrains.kotlin.analysis.project.structure.KtModule
+import org.jetbrains.kotlin.analysis.project.structure.KtDanglingFileModule
 import org.jetbrains.kotlin.platform.TargetPlatform
 import org.jetbrains.kotlin.psi.KtCodeFragment
+import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.psiUtil.createSmartPointer
 import org.jetbrains.kotlin.resolve.PlatformDependentAnalyzerServices
 import java.util.Objects
 
-public class KtCodeFragmentModuleImpl(
-    codeFragment: KtCodeFragment,
+public class KtDanglingFileModuleImpl(
+    file: KtFile,
     override val contextModule: KtModule
-) : KtCodeFragmentModule {
-    private val codeFragmentRef = codeFragment.createSmartPointer()
+) : KtDanglingFileModule {
+    override val isCodeFragment: Boolean = file is KtCodeFragment
 
-    override val codeFragment: KtCodeFragment
-        get() = codeFragmentRef.element?.takeIf { it.isValid } ?: error("Code fragment module is invalid")
+    private val fileRef = file.createSmartPointer()
+
+    init {
+        require(contextModule != this)
+
+        if (contextModule is KtDanglingFileModule) {
+            // Only code fragments can depend on dangling files.
+            // This is needed for completion, inspections and refactorings.
+            require(file is KtCodeFragment)
+        }
+    }
+
+    override val file: KtFile
+        get() = fileRef.element?.takeIf { it.isValid } ?: error("Dangling file module is invalid")
 
     override val project: Project
         get() = contextModule.project
@@ -34,7 +47,7 @@ public class KtCodeFragmentModuleImpl(
         get() = contextModule.analyzerServices
 
     override val contentScope: GlobalSearchScope
-        get() = GlobalSearchScope.fileScope(codeFragment)
+        get() = GlobalSearchScope.fileScope(file)
 
     override val directRegularDependencies: List<KtModule>
         get() = contextModule.directRegularDependencies
@@ -51,16 +64,16 @@ public class KtCodeFragmentModuleImpl(
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
 
-        if (other is KtCodeFragmentModuleImpl) {
-            val selfCodeFragment = this.codeFragmentRef.element
-            val otherCodeFragment = other.codeFragmentRef.element
-            return selfCodeFragment != null && selfCodeFragment == otherCodeFragment && contextModule == other.contextModule
+        if (other is KtDanglingFileModuleImpl) {
+            val selfFile = this.fileRef.element
+            val otherFile = other.fileRef.element
+            return selfFile != null && selfFile == otherFile && contextModule == other.contextModule
         }
 
         return false
     }
 
     override fun hashCode(): Int {
-        return Objects.hash(codeFragmentRef.element, contextModule)
+        return Objects.hash(fileRef.element, contextModule)
     }
 }