Native: report a warning on invalid characters in identifiers

This will become an error in Kotlin 1.7.

^KT-46182 Fixed

native/frontend/src/org/jetbrains/kotlin/resolve/konan/diagnostics/DefaultErrorMessagesNative.kt

@@ -41,6 +41,7 @@ private val DIAGNOSTIC_FACTORY_TO_RENDERER by lazy {
             "@ThreadLocal is applicable only to property with backing field, to property with delegation or to objects"
         )
         put(ErrorsNative.INAPPLICABLE_THREAD_LOCAL_TOP_LEVEL, "@ThreadLocal is applicable only to top level declarations")
+        put(ErrorsNative.INVALID_CHARACTERS_NATIVE, "Name {0}", Renderers.STRING);
     }
 }
 

native/frontend/src/org/jetbrains/kotlin/resolve/konan/diagnostics/ErrorsNative.kt

@@ -5,11 +5,10 @@
 
 package org.jetbrains.kotlin.resolve.konan.diagnostics
 
+import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
-import org.jetbrains.kotlin.diagnostics.DiagnosticFactory0
-import org.jetbrains.kotlin.diagnostics.DiagnosticFactory1
-import org.jetbrains.kotlin.diagnostics.Errors
-import org.jetbrains.kotlin.diagnostics.Severity
+import org.jetbrains.kotlin.diagnostics.*
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.KtDeclaration
 import org.jetbrains.kotlin.psi.KtElement
@@ -35,6 +34,9 @@ object ErrorsNative {
     val INAPPLICABLE_THREAD_LOCAL_TOP_LEVEL = DiagnosticFactory0.create<KtElement>(Severity.ERROR)
     @JvmField
     val VARIABLE_IN_ENUM = DiagnosticFactory0.create<KtElement>(Severity.WARNING)
+    @JvmField
+    val INVALID_CHARACTERS_NATIVE = DiagnosticFactoryForDeprecation1.create<PsiElement, String>(LanguageFeature.ProhibitInvalidCharsInNativeIdentifiers)
+
     init {
         Errors.Initializer.initializeFactoryNames(ErrorsNative::class.java)
     }

native/frontend/src/org/jetbrains/kotlin/resolve/konan/diagnostics/NativeIdentifierChecker.kt

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.resolve.konan.diagnostics
+
+import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.config.LanguageVersionSettings
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.diagnostics.DiagnosticSink
+import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.resolve.IdentifierChecker
+import org.jetbrains.kotlin.resolve.checkers.DeclarationChecker
+import org.jetbrains.kotlin.resolve.checkers.DeclarationCheckerContext
+
+// Note: IdentifierChecker doesn't check typealiases, so inheriting DeclarationChecker as well.
+// Originally based on JvmSimpleNameBacktickChecker.
+class NativeIdentifierChecker(private val languageVersionSettings: LanguageVersionSettings) : IdentifierChecker, DeclarationChecker {
+    // Also includes characters used by IR mangler (see MangleConstant).
+    private val invalidChars = setOf(
+        '.', ';', ',', '(', ')', '[', ']', '{', '}', '/', '<', '>',
+        ':', '\\', '$', '&', '~', '*', '?', '#', '|', '§', '%', '@',
+    )
+
+    override fun checkIdentifier(simpleNameExpression: KtSimpleNameExpression, diagnosticHolder: DiagnosticSink) {
+        reportIfNeeded(simpleNameExpression.getReferencedName(), { simpleNameExpression.getIdentifier() }, diagnosticHolder)
+    }
+
+    override fun checkDeclaration(declaration: KtDeclaration, diagnosticHolder: DiagnosticSink) {
+        if (declaration is KtDestructuringDeclaration) {
+            declaration.entries.forEach { checkNamed(it, diagnosticHolder) }
+        }
+        if (declaration is KtCallableDeclaration) {
+            declaration.valueParameters.forEach { checkNamed(it, diagnosticHolder) }
+        }
+        if (declaration is KtTypeParameterListOwner) {
+            declaration.typeParameters.forEach { checkNamed(it, diagnosticHolder) }
+        }
+        if (declaration is KtNamedDeclaration) {
+            checkNamed(declaration, diagnosticHolder)
+        }
+    }
+
+    override fun check(declaration: KtDeclaration, descriptor: DeclarationDescriptor, context: DeclarationCheckerContext) {
+        if (declaration is KtTypeAlias) {
+            checkNamed(declaration, context.trace)
+        }
+    }
+
+    private fun checkNamed(declaration: KtNamedDeclaration, diagnosticHolder: DiagnosticSink) {
+        val name = declaration.name ?: return
+
+        reportIfNeeded(name, { declaration.nameIdentifier ?: declaration }, diagnosticHolder)
+    }
+
+    private fun reportIfNeeded(name: String, reportOn: () -> PsiElement?, diagnosticHolder: DiagnosticSink) {
+        val text = KtPsiUtil.unquoteIdentifier(name)
+        when {
+            text.isEmpty() -> {
+                diagnosticHolder.report(
+                    ErrorsNative.INVALID_CHARACTERS_NATIVE.on(
+                        languageVersionSettings,
+                        reportOn() ?: return,
+                        "should not be empty"
+                    )
+                )
+            }
+            text.any { it in invalidChars } -> {
+                diagnosticHolder.report(
+                    ErrorsNative.INVALID_CHARACTERS_NATIVE.on(
+                        languageVersionSettings,
+                        reportOn() ?: return,
+                        "contains illegal characters: " +
+                                invalidChars.intersect(text.toSet()).joinToString("", prefix = "\"", postfix = "\"")
+                    )
+                )
+            }
+        }
+    }
+}

native/frontend/src/org/jetbrains/kotlin/resolve/konan/platform/NativePlatformConfigurator.kt

@@ -18,10 +18,7 @@ import org.jetbrains.kotlin.resolve.calls.checkers.TypeOfChecker
 import org.jetbrains.kotlin.resolve.checkers.ExpectedActualDeclarationChecker
 import org.jetbrains.kotlin.resolve.inline.ReasonableInlineRule
 import org.jetbrains.kotlin.resolve.jvm.checkers.SuperCallWithDefaultArgumentsChecker
-import org.jetbrains.kotlin.resolve.konan.diagnostics.NativeSharedImmutableChecker
-import org.jetbrains.kotlin.resolve.konan.diagnostics.NativeThreadLocalChecker
-import org.jetbrains.kotlin.resolve.konan.diagnostics.NativeThrowsChecker
-import org.jetbrains.kotlin.resolve.konan.diagnostics.NativeTopLevelSingletonChecker
+import org.jetbrains.kotlin.resolve.konan.diagnostics.*
 
 object NativePlatformConfigurator : PlatformConfiguratorBase(
     additionalCallCheckers = listOf(
@@ -35,6 +32,7 @@ object NativePlatformConfigurator : PlatformConfiguratorBase(
 ) {
     override fun configureModuleComponents(container: StorageComponentContainer, languageVersionSettings: LanguageVersionSettings) {
         container.useInstance(NativeInliningRule)
+        container.useImpl<NativeIdentifierChecker>()
     }
 
     override fun configureModuleDependentCheckers(container: StorageComponentContainer) {