Report an error when variance is specified for a function or property type parameter

compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/Errors.java

@@ -187,6 +187,8 @@ public interface Errors {
     DiagnosticFactory2<JetSimpleNameExpression, JetTypeConstraint, JetTypeParameterListOwner> NAME_IN_CONSTRAINT_IS_NOT_A_TYPE_PARAMETER =
             DiagnosticFactory2.create(ERROR);
 
+    SimpleDiagnosticFactory<JetTypeParameter> VARIANCE_ON_FUNCTION_OR_PROPERTY_PARAMETER = SimpleDiagnosticFactory.create(ERROR, VARIANCE_MODIFIER);
+
     // Members
 
     SimpleDiagnosticFactory<PsiElement> PACKAGE_MEMBER_CANNOT_BE_PROTECTED = SimpleDiagnosticFactory.create(ERROR);

compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/PositioningStrategies.java

@@ -27,6 +27,7 @@ import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lexer.JetKeywordToken;
 import org.jetbrains.jet.lexer.JetTokens;
 
+import java.util.Arrays;
 import java.util.List;
 
 /**
@@ -182,6 +183,27 @@ public class PositioningStrategies {
         };
     }
 
+    public static final PositioningStrategy<JetModifierListOwner> VARIANCE_MODIFIER = modifierSetPosition(JetTokens.IN_KEYWORD, JetTokens.OUT_KEYWORD);
+
+    public static PositioningStrategy<JetModifierListOwner> modifierSetPosition(final JetKeywordToken... tokens) {
+        return new PositioningStrategy<JetModifierListOwner>() {
+            @NotNull
+            @Override
+            public List<TextRange> mark(@NotNull JetModifierListOwner modifierListOwner) {
+                JetModifierList modifierList = modifierListOwner.getModifierList();
+                assert modifierList != null : "No modifier list, but modifier has been found by the analyzer";
+
+                for (JetKeywordToken token : tokens) {
+                    ASTNode node = modifierList.getModifierNode(token);
+                    if (node != null) {
+                        return markNode(node);
+                    }
+                }
+                throw new IllegalStateException("None of the modifiers is found: " + Arrays.asList(tokens));
+            }
+        };
+    }
+
     public static final PositioningStrategy<JetArrayAccessExpression> ARRAY_ACCESS = new PositioningStrategy<JetArrayAccessExpression>() {
         @NotNull
         @Override

compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/rendering/DefaultErrorMessages.java

@@ -319,6 +319,8 @@ public class DefaultErrorMessages {
         MAP.put(AUTOCAST_IMPOSSIBLE, "Automatic cast to ''{0}'' is impossible, because ''{1}'' could have changed since the is-check", RENDER_TYPE,
                 NAME);
 
+        MAP.put(VARIANCE_ON_FUNCTION_OR_PROPERTY_PARAMETER, "Variance annotations are only allowed for type parameters of classes and traits");
+
         MAP.put(TYPE_MISMATCH_IN_FOR_LOOP, "The loop iterates over values of type {0} but the parameter is declared to be {1}", RENDER_TYPE,
                 RENDER_TYPE);
         MAP.put(TYPE_MISMATCH_IN_CONDITION, "Condition must be of type jet.Boolean, but is of type {0}", RENDER_TYPE);

compiler/frontend/src/org/jetbrains/jet/lang/resolve/DescriptorResolver.java

@@ -522,6 +522,11 @@ public class DescriptorResolver {
             int index,
             BindingTrace trace
     ) {
+        if (typeParameter.getVariance() != Variance.INVARIANT) {
+            assert !(containingDescriptor instanceof ClassifierDescriptor) : "This method is intended for functions/properties";
+            trace.report(VARIANCE_ON_FUNCTION_OR_PROPERTY_PARAMETER.on(typeParameter));
+        }
+
         // TODO: Annotations are not resolved!
         TypeParameterDescriptorImpl typeParameterDescriptor = TypeParameterDescriptorImpl.createForFurtherModification(
                 containingDescriptor,

compiler/testData/diagnostics/tests/declarationChecks/VarianceOnFunctionAndPropertyTypeParameters.kt

@@ -0,0 +1,17 @@
+fun <<!VARIANCE_ON_FUNCTION_OR_PROPERTY_PARAMETER!>in<!> T> f() {
+    
+}
+
+fun <<!VARIANCE_ON_FUNCTION_OR_PROPERTY_PARAMETER!>out<!> T> g() {
+
+}
+
+fun <<!VARIANCE_ON_FUNCTION_OR_PROPERTY_PARAMETER!>out<!> T, <!VARIANCE_ON_FUNCTION_OR_PROPERTY_PARAMETER!>in<!> X, Y> h() {
+
+}
+
+val <<!VARIANCE_ON_FUNCTION_OR_PROPERTY_PARAMETER!>out<!> T> T.x: Int
+    get() = 1
+
+val <<!VARIANCE_ON_FUNCTION_OR_PROPERTY_PARAMETER!>in<!> T> T.y: Int
+    get() = 1

compiler/testData/diagnostics/tests/inference/listConstructor.kt

@@ -22,7 +22,7 @@ fun test() {
 
 fun arrayList<T>(vararg values: T) : ArrayList<T> = values.toCollection(ArrayList<T>(values.size))
 
-fun <in T, C: MutableCollection<in T>> Array<T>.toCollection(result: C) : C {
+fun <T, C: MutableCollection<in T>> Array<T>.toCollection(result: C) : C {
     for (element in this) result.add(element)
     return result
 }

compiler/testData/diagnostics/tests/inference/regressions/kt1718.kt

@@ -12,4 +12,4 @@ fun test() {
 
 //from library
 fun arrayList<T>(vararg <!UNUSED_PARAMETER!>values<!>: T) : ArrayList<T> {<!NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY!>}<!>
-fun <in T> Iterable<T>.plus(<!UNUSED_PARAMETER!>elements<!>: Iterable<T>): List<T> {<!NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY!>}<!>
+fun <T> Iterable<T>.plus(<!UNUSED_PARAMETER!>elements<!>: Iterable<T>): List<T> {<!NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY!>}<!>

compiler/testData/diagnostics/tests/inference/regressions/kt2179.kt

@@ -35,7 +35,7 @@ fun <T, R, C: MutableCollection<in R>> Collection<T>.mapTo(result: C, transform
   return result
 }
 
-fun <in T, C: MutableCollection<in T>> Array<T>.toCollection(result: C) : C {
+fun <T, C: MutableCollection<in T>> Array<T>.toCollection(result: C) : C {
     for (element in this) result.add(element)
     return result
 }

compiler/testData/diagnostics/tests/inference/regressions/kt2324.kt

@@ -27,7 +27,7 @@ fun assertEquals(<!UNUSED_PARAMETER!>expected<!>: Any?, <!UNUSED_PARAMETER!>actu
 
 fun arrayList<T>(vararg values: T) : ArrayList<T> = values.toCollection(ArrayList<T>(values.size))
 
-fun <in T, C: MutableCollection<in T>> Array<T>.toCollection(result: C) : C {
+fun <T, C: MutableCollection<in T>> Array<T>.toCollection(result: C) : C {
     for (element in this) result.add(element)
     return result
 }

compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunInParam.kt

@@ -1,3 +0,0 @@
-package test
-
-fun <in T> f() = 1

compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunInParam.txt

@@ -1,3 +0,0 @@
-namespace test
-
-internal final fun </*0*/ in T : jet.Any?>f(): jet.Int

compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunOutParam.kt

@@ -1,3 +0,0 @@
-package test
-
-fun <out T> f() = 1

compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunOutParam.txt

@@ -1,3 +0,0 @@
-namespace test
-
-internal final fun </*0*/ out T : jet.Any?>f(): jet.Int

compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunParamReferencesParam2.kt

@@ -1,3 +0,0 @@
-package test
-
-fun <in P, Q : P> funParamReferencesParam() = 1

compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunParamReferencesParam2.txt

@@ -1,3 +0,0 @@
-namespace test
-
-internal final fun </*0*/ in P : jet.Any?, /*1*/ Q : P>funParamReferencesParam(): jet.Int

compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunTwoTypeParams2.kt

@@ -1,3 +0,0 @@
-package test
-
-fun <P, in Q> funTwoTypeParams() = 1

compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunTwoTypeParams2.txt

@@ -1,3 +0,0 @@
-namespace test
-
-internal final fun </*0*/ P : jet.Any?, /*1*/ in Q : jet.Any?>funTwoTypeParams(): jet.Int

compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java

@@ -1462,6 +1462,11 @@ public class JetDiagnosticsTestGenerated extends AbstractDiagnosticsTestWithEage
                 doTest("compiler/testData/diagnostics/tests/declarationChecks/RedeclarationsInMultiDecl.kt");
             }
             
+            @TestMetadata("VarianceOnFunctionAndPropertyTypeParameters.kt")
+            public void testVarianceOnFunctionAndPropertyTypeParameters() throws Exception {
+                doTest("compiler/testData/diagnostics/tests/declarationChecks/VarianceOnFunctionAndPropertyTypeParameters.kt");
+            }
+            
             @TestMetadata("compiler/testData/diagnostics/tests/declarationChecks/multiDeclarations")
             public static class MultiDeclarations extends AbstractDiagnosticsTestWithEagerResolve {
                 public void testAllFilesPresentInMultiDeclarations() throws Exception {

compiler/tests/org/jetbrains/jet/jvm/compiler/LoadCompiledKotlinTestGenerated.java

@@ -347,16 +347,6 @@ public class LoadCompiledKotlinTestGenerated extends AbstractLoadCompiledKotlinT
                 doTest("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunGenericParam.kt");
             }
             
-            @TestMetadata("FunInParam.kt")
-            public void testFunInParam() throws Exception {
-                doTest("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunInParam.kt");
-            }
-            
-            @TestMetadata("FunOutParam.kt")
-            public void testFunOutParam() throws Exception {
-                doTest("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunOutParam.kt");
-            }
-            
             @TestMetadata("FunParamParam.kt")
             public void testFunParamParam() throws Exception {
                 doTest("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunParamParam.kt");
@@ -372,11 +362,6 @@ public class LoadCompiledKotlinTestGenerated extends AbstractLoadCompiledKotlinT
                 doTest("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunParamReferencesParam.kt");
             }
             
-            @TestMetadata("FunParamReferencesParam2.kt")
-            public void testFunParamReferencesParam2() throws Exception {
-                doTest("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunParamReferencesParam2.kt");
-            }
-            
             @TestMetadata("FunParamTwoUpperBounds.kt")
             public void testFunParamTwoUpperBounds() throws Exception {
                 doTest("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunParamTwoUpperBounds.kt");
@@ -412,11 +397,6 @@ public class LoadCompiledKotlinTestGenerated extends AbstractLoadCompiledKotlinT
                 doTest("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunTwoTypeParams.kt");
             }
             
-            @TestMetadata("FunTwoTypeParams2.kt")
-            public void testFunTwoTypeParams2() throws Exception {
-                doTest("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunTwoTypeParams2.kt");
-            }
-            
         }
         
         @TestMetadata("compiler/testData/loadKotlin/fun/genericWithoutTypeVariables")

compiler/tests/org/jetbrains/jet/lang/resolve/lazy/LazyResolveNamespaceComparingTestGenerated.java

@@ -15,16 +15,13 @@
  */
 package org.jetbrains.jet.lang.resolve.lazy;
 
-import junit.framework.Assert;
 import junit.framework.Test;
 import junit.framework.TestSuite;
-
-import java.io.File;
 import org.jetbrains.jet.JetTestUtils;
 import org.jetbrains.jet.test.InnerTestClasses;
 import org.jetbrains.jet.test.TestMetadata;
 
-import org.jetbrains.jet.lang.resolve.lazy.AbstractLazyResolveNamespaceComparingTest;
+import java.io.File;
 
 /** This class is generated by {@link org.jetbrains.jet.generators.tests.GenerateTests}. DO NOT MODIFY MANUALLY */
 @InnerTestClasses({LazyResolveNamespaceComparingTestGenerated.LoadKotlin.class, LazyResolveNamespaceComparingTestGenerated.LoadJava.class, LazyResolveNamespaceComparingTestGenerated.NamespaceComparator.class})
@@ -349,16 +346,6 @@ public class LazyResolveNamespaceComparingTestGenerated extends AbstractLazyReso
                     doTestSinglePackage("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunGenericParam.kt");
                 }
                 
-                @TestMetadata("FunInParam.kt")
-                public void testFunInParam() throws Exception {
-                    doTestSinglePackage("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunInParam.kt");
-                }
-                
-                @TestMetadata("FunOutParam.kt")
-                public void testFunOutParam() throws Exception {
-                    doTestSinglePackage("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunOutParam.kt");
-                }
-                
                 @TestMetadata("FunParamParam.kt")
                 public void testFunParamParam() throws Exception {
                     doTestSinglePackage("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunParamParam.kt");
@@ -374,11 +361,6 @@ public class LazyResolveNamespaceComparingTestGenerated extends AbstractLazyReso
                     doTestSinglePackage("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunParamReferencesParam.kt");
                 }
                 
-                @TestMetadata("FunParamReferencesParam2.kt")
-                public void testFunParamReferencesParam2() throws Exception {
-                    doTestSinglePackage("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunParamReferencesParam2.kt");
-                }
-                
                 @TestMetadata("FunParamTwoUpperBounds.kt")
                 public void testFunParamTwoUpperBounds() throws Exception {
                     doTestSinglePackage("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunParamTwoUpperBounds.kt");
@@ -414,11 +396,6 @@ public class LazyResolveNamespaceComparingTestGenerated extends AbstractLazyReso
                     doTestSinglePackage("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunTwoTypeParams.kt");
                 }
                 
-                @TestMetadata("FunTwoTypeParams2.kt")
-                public void testFunTwoTypeParams2() throws Exception {
-                    doTestSinglePackage("compiler/testData/loadKotlin/fun/genericWithTypeVariables/FunTwoTypeParams2.kt");
-                }
-                
             }
             
             @TestMetadata("compiler/testData/loadKotlin/fun/genericWithoutTypeVariables")