[KT-58817] Implicit import issues cannot be reported

To be reported with [1] imports require source. It was missing for
implicit script imports.

`FirScriptConfiguratorExtensionImpl` was extended and now adds fake
source elements (users don't see imports in the source code).

Since diagnostics for implicit import statements are meaningless for
IDE, they are suppressed in `LLFirDiagnosticReporter`.

----------------------------------------------------------------------
[1]: DiagnosticReporter.reportOn()

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostics/LLFirDiagnosticReporter.kt

@@ -7,6 +7,8 @@ package org.jetbrains.kotlin.analysis.low.level.api.fir.diagnostics
 
 import com.intellij.psi.PsiElement
 import org.jetbrains.kotlin.AbstractKtSourceElement
+import org.jetbrains.kotlin.KtFakeSourceElement
+import org.jetbrains.kotlin.KtFakeSourceElementKind
 import org.jetbrains.kotlin.analysis.low.level.api.fir.util.addValueFor
 import org.jetbrains.kotlin.diagnostics.*
 
@@ -18,6 +20,10 @@ internal class LLFirDiagnosticReporter : DiagnosticReporter() {
         if (diagnostic == null) return
         if (context.isDiagnosticSuppressed(diagnostic)) return
 
+        // Implicit imports for scripts are currently implemented via FIR-tree mutation (they do not exist in default importing scopes).
+        // So as a temporary solution we filter out related diagnostics here.
+        if (diagnostic.isAboutImplicitImport()) return
+
         val psiDiagnostic = when (diagnostic) {
             is KtPsiDiagnostic -> diagnostic
             is KtLightDiagnostic -> diagnostic.toPsiDiagnostic()
@@ -51,6 +57,10 @@ internal class LLFirDiagnosticReporter : DiagnosticReporter() {
     }
 }
 
+private fun KtDiagnostic.isAboutImplicitImport() =
+    (element is KtFakeSourceElement && (element as KtFakeSourceElement).kind == KtFakeSourceElementKind.ImplicitImport)
+
+
 private fun KtLightDiagnostic.toPsiDiagnostic(): KtPsiDiagnostic {
     val psiSourceElement = element.unwrapToKtPsiSourceElement()
         ?: error("Diagnostic should be created from PSI in IDE")

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirImportsChecker.kt

@@ -10,7 +10,6 @@ import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.diagnostics.reportOn
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.checkers.expression.FirDeprecationChecker
-import org.jetbrains.kotlin.fir.declarations.fullyExpandedClass
 import org.jetbrains.kotlin.fir.analysis.checkers.unsubstitutedScope
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.analysis.getSourceForImportSegment
@@ -128,7 +127,7 @@ object FirImportsChecker : FirFileChecker() {
         }
 
         resolvedDeclaration?.let {
-            val source = import.getSourceForImportSegment(0)
+            val source = import.getSourceForImportSegment(0) ?: import.source
             reporter.reportOn(source, FirErrors.INVISIBLE_REFERENCE, it.symbol, context)
             return
         }

compiler/frontend.common/src/org/jetbrains/kotlin/KtSourceElement.kt

@@ -272,6 +272,9 @@ sealed class KtFakeSourceElementKind(final override val shouldSkipErrorTypeRepor
 
     // When property doesn't have an initializer and explicit return type, but its getter's return type is specified
     object PropertyTypeFromGetterReturnType : KtFakeSourceElementKind()
+
+    // Scripts get implicit imports from their configurations
+    object ImplicitImport : KtFakeSourceElementKind()
 }
 
 sealed class AbstractKtSourceElement {

plugins/scripting/scripting-compiler/src/org/jetbrains/kotlin/scripting/compiler/plugin/services/FirScriptConfigurationExtensionImpl.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.scripting.compiler.plugin.services
 
+import com.intellij.openapi.project.Project
 import org.jetbrains.kotlin.*
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
@@ -27,6 +28,7 @@ import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.KtFile
+import org.jetbrains.kotlin.psi.KtPsiFactory
 import org.jetbrains.kotlin.scripting.definitions.annotationsForSamWithReceivers
 import org.jetbrains.kotlin.scripting.resolve.KtFileScriptSource
 import org.jetbrains.kotlin.scripting.resolve.VirtualFileScriptSource
@@ -61,6 +63,10 @@ class FirScriptConfiguratorExtensionImpl(
                 val stripped = if (endsWithStar) trimmed.substring(0, trimmed.length - 2) else trimmed
                 val fqName = FqName.fromSegments(stripped.split("."))
                 fileBuilder.imports += buildImport {
+                    fileBuilder.sourceFile?.project()?.let {
+                        val dummyElement = KtPsiFactory(it, markGenerated = true).createColon()
+                        source = KtFakeSourceElement(dummyElement, KtFakeSourceElementKind.ImplicitImport)
+                    }
                     importedFqName = fqName
                     isAllUnder = endsWithStar
                 }
@@ -148,6 +154,8 @@ class FirScriptConfiguratorExtensionImpl(
     }
 }
 
+private fun KtSourceFile.project(): Project? = (toSourceCode() as? KtFileScriptSource)?.ktFile?.project
+
 fun KtSourceFile.toSourceCode(): SourceCode? = when (this) {
     is KtPsiSourceFile -> (psiFile as? KtFile)?.let(::KtFileScriptSource) ?: VirtualFileScriptSource(psiFile.virtualFile)
     is KtVirtualFileSourceFile -> VirtualFileScriptSource(virtualFile)