Prohibit operator mod as declaration and calls that resolved via it

#KT-24197 Fixed

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java

@@ -747,7 +747,9 @@ public interface Errors {
     DiagnosticFactory2<KtBinaryExpression, KotlinType, KotlinType> FORBIDDEN_IDENTITY_EQUALS = DiagnosticFactory2.create(ERROR);
 
     DiagnosticFactory2<PsiElement, FunctionDescriptor, String> DEPRECATED_BINARY_MOD = DiagnosticFactory2.create(WARNING);
+    DiagnosticFactory2<PsiElement, FunctionDescriptor, String> FORBIDDEN_BINARY_MOD = DiagnosticFactory2.create(ERROR);
     DiagnosticFactory2<PsiElement, FunctionDescriptor, String> DEPRECATED_BINARY_MOD_AS_REM = DiagnosticFactory2.create(WARNING);
+    DiagnosticFactory2<PsiElement, FunctionDescriptor, String> FORBIDDEN_BINARY_MOD_AS_REM = DiagnosticFactory2.create(ERROR);
 
     DiagnosticFactory0<KtArrayAccessExpression> NO_GET_METHOD = DiagnosticFactory0.create(ERROR, ARRAY_ACCESS);
     DiagnosticFactory0<KtArrayAccessExpression> NO_SET_METHOD = DiagnosticFactory0.create(ERROR, ARRAY_ACCESS);

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java

@@ -396,7 +396,9 @@ public class DefaultErrorMessages {
         MAP.put(FORBIDDEN_IDENTITY_EQUALS, "Identity equality for arguments of types {0} and {1} is forbidden", RENDER_TYPE, RENDER_TYPE);
 
         MAP.put(DEPRECATED_BINARY_MOD, "Deprecated convention for ''{0}''. Use ''{1}''", NAME, STRING);
+        MAP.put(FORBIDDEN_BINARY_MOD, "Convention for ''{0}'' is forbidden. Use ''{1}''", NAME, STRING);
         MAP.put(DEPRECATED_BINARY_MOD_AS_REM, "''%'' is resolved to deprecated ''{0}'' operator. Replace with ''.{0}'' or add operator ''{1}''", NAME, STRING);
+        MAP.put(FORBIDDEN_BINARY_MOD_AS_REM, "''%'' is resolved to forbidden ''{0}'' operator. Replace with ''.{0}'' or add operator ''{1}''", NAME, STRING);
 
         MAP.put(NO_GET_METHOD, "No get method providing array access");
         MAP.put(NO_SET_METHOD, "No set method providing array access");

compiler/frontend/src/org/jetbrains/kotlin/resolve/OperatorModifierChecker.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.resolve
 
 import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
@@ -50,10 +51,18 @@ object OperatorModifierChecker {
                     checkSupportsFeature(LanguageFeature.OperatorProvideDelegate, languageVersionSettings, diagnosticHolder, modifier)
             }
 
-            if (functionDescriptor.name in REM_TO_MOD_OPERATION_NAMES.values
-                && languageVersionSettings.supportsFeature(LanguageFeature.OperatorRem)) {
+            if (functionDescriptor.name in REM_TO_MOD_OPERATION_NAMES.values &&
+                languageVersionSettings.supportsFeature(LanguageFeature.OperatorRem)
+            ) {
+                val diagnosticFactory = if (!KotlinBuiltIns.isUnderKotlinPackage(descriptor) &&
+                    languageVersionSettings.supportsFeature(LanguageFeature.ProhibitOperatorMod)
+                )
+                    Errors.FORBIDDEN_BINARY_MOD
+                else
+                    Errors.DEPRECATED_BINARY_MOD
+
                 val newNameConvention = REM_TO_MOD_OPERATION_NAMES.inverse()[functionDescriptor.name]
-                diagnosticHolder.report(Errors.DEPRECATED_BINARY_MOD.on(modifier, functionDescriptor, newNameConvention!!.asString()))
+                diagnosticHolder.report(diagnosticFactory.on(modifier, functionDescriptor, newNameConvention!!.asString()))
             }
 
             return

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/checkers/OperatorCallChecker.kt

@@ -117,16 +117,26 @@ private fun checkModConvention(
 
     if (KotlinBuiltIns.isUnderKotlinPackage(descriptor)) {
         if (shouldWarnAboutDeprecatedModFromBuiltIns(languageVersionSettings)) {
-            addWarningAboutDeprecatedMod(descriptor, diagnosticHolder, modifier)
+            warnAboutDeprecatedOrForbiddenMod(descriptor, diagnosticHolder, modifier, languageVersionSettings)
         }
     } else {
         if (languageVersionSettings.supportsFeature(LanguageFeature.OperatorRem)) {
-            addWarningAboutDeprecatedMod(descriptor, diagnosticHolder, modifier)
+            warnAboutDeprecatedOrForbiddenMod(descriptor, diagnosticHolder, modifier, languageVersionSettings)
         }
     }
 }
 
-private fun addWarningAboutDeprecatedMod(descriptor: FunctionDescriptor, diagnosticHolder: DiagnosticSink, reportOn: PsiElement) {
+private fun warnAboutDeprecatedOrForbiddenMod(
+    descriptor: FunctionDescriptor,
+    diagnosticHolder: DiagnosticSink,
+    reportOn: PsiElement,
+    languageVersionSettings: LanguageVersionSettings
+) {
+    val diagnosticFactory = if (languageVersionSettings.supportsFeature(LanguageFeature.ProhibitOperatorMod))
+        Errors.FORBIDDEN_BINARY_MOD_AS_REM
+    else
+        Errors.DEPRECATED_BINARY_MOD_AS_REM
+
     val newNameConvention = OperatorConventions.REM_TO_MOD_OPERATION_NAMES.inverse()[descriptor.name]
-    diagnosticHolder.report(Errors.DEPRECATED_BINARY_MOD_AS_REM.on(reportOn, descriptor, newNameConvention!!.asString()))
+    diagnosticHolder.report(diagnosticFactory.on(reportOn, descriptor, newNameConvention!!.asString()))
 }

compiler/testData/diagnostics/tests/operatorRem/forbiddenModOperatorConvention.kt

@@ -0,0 +1,32 @@
+// !LANGUAGE: +ProhibitOperatorMod
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+object ModAndRem {
+    <!FORBIDDEN_BINARY_MOD!>operator<!> fun mod(x: Int) {}
+    operator fun rem(x: Int) {}
+
+    <!FORBIDDEN_BINARY_MOD!>operator<!> fun modAssign(x: Int) {}
+    operator fun remAssign(x: Int) {}
+}
+
+object JustMod {
+    <!FORBIDDEN_BINARY_MOD!>operator<!> fun mod(x: Int) {}
+    <!FORBIDDEN_BINARY_MOD!>operator<!> fun modAssign(x: Int) {}
+}
+
+fun foo() {
+    ModAndRem % 1
+    ModAndRem.mod(1)
+    ModAndRem.rem(1)
+
+    JustMod <!FORBIDDEN_BINARY_MOD_AS_REM!>%<!> 1
+    JustMod.mod(1)
+
+    val r = ModAndRem
+    r %= 1
+    r.remAssign(1)
+
+    val m = JustMod
+    m <!FORBIDDEN_BINARY_MOD_AS_REM!>%=<!> 1
+    m.modAssign(1)
+}

compiler/testData/diagnostics/tests/operatorRem/forbiddenModOperatorConvention.txt

@@ -0,0 +1,23 @@
+package
+
+public fun foo(): kotlin.Unit
+
+public object JustMod {
+    private constructor JustMod()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final operator fun mod(/*0*/ x: kotlin.Int): kotlin.Unit
+    public final operator fun modAssign(/*0*/ x: kotlin.Int): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public object ModAndRem {
+    private constructor ModAndRem()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final operator fun mod(/*0*/ x: kotlin.Int): kotlin.Unit
+    public final operator fun modAssign(/*0*/ x: kotlin.Int): kotlin.Unit
+    public final operator fun rem(/*0*/ x: kotlin.Int): kotlin.Unit
+    public final operator fun remAssign(/*0*/ x: kotlin.Int): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -13813,6 +13813,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 runTest("compiler/testData/diagnostics/tests/operatorRem/doNotResolveToInapplicableRem.kt");
             }
 
+            @TestMetadata("forbiddenModOperatorConvention.kt")
+            public void testForbiddenModOperatorConvention() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/operatorRem/forbiddenModOperatorConvention.kt");
+            }
+
             @TestMetadata("modWithRemAssign.kt")
             public void testModWithRemAssign() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/operatorRem/modWithRemAssign.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java

@@ -13813,6 +13813,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/operatorRem/doNotResolveToInapplicableRem.kt");
             }
 
+            @TestMetadata("forbiddenModOperatorConvention.kt")
+            public void testForbiddenModOperatorConvention() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/operatorRem/forbiddenModOperatorConvention.kt");
+            }
+
             @TestMetadata("modWithRemAssign.kt")
             public void testModWithRemAssign() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/operatorRem/modWithRemAssign.kt");

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -77,6 +77,7 @@ enum class LanguageFeature(
     AllowContractsForCustomFunctions(KOTLIN_1_3, kind = UNSTABLE_FEATURE),
     ProhibitLocalAnnotations(KOTLIN_1_3, kind = BUG_FIX),
     ProhibitSmartcastsOnLocalDelegatedProperty(KOTLIN_1_3, kind = BUG_FIX),
+    ProhibitOperatorMod(KOTLIN_1_3, kind = BUG_FIX),
 
     StrictJavaNullabilityAssertions(sinceVersion = null, defaultState = State.DISABLED),
     ProperIeee754Comparisons(sinceVersion = null, defaultState = State.DISABLED),