sometimes it not permitted to redeclare variable in nested scope (KT-527)

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

@@ -44,7 +44,10 @@ public interface Errors {
         }
     };
     UnresolvedReferenceDiagnosticFactory UNRESOLVED_REFERENCE = new UnresolvedReferenceDiagnosticFactory("Unresolved reference");
-    RedeclarationDiagnosticFactory REDECLARATION = RedeclarationDiagnosticFactory.INSTANCE;
+
+    RedeclarationDiagnosticFactory REDECLARATION = RedeclarationDiagnosticFactory.REDECLARATION;
+    RedeclarationDiagnosticFactory NAME_SHADOWING = RedeclarationDiagnosticFactory.NAME_SHADOWING;
+
     PsiElementOnlyDiagnosticFactory2<PsiElement, JetType, JetType> TYPE_MISMATCH = PsiElementOnlyDiagnosticFactory2.create(ERROR, "Type mismatch: inferred type is {1} but {0} was expected");
     ParameterizedDiagnosticFactory1<Collection<JetKeywordToken>> INCOMPATIBLE_MODIFIERS = new ParameterizedDiagnosticFactory1<Collection<JetKeywordToken>>(ERROR, "Incompatible modifiers: ''{0}''") {
         @Override

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

@@ -15,8 +15,8 @@ import static org.jetbrains.jet.lang.diagnostics.Severity.ERROR;
 public interface RedeclarationDiagnostic extends DiagnosticWithPsiElement<PsiElement> {
     public class SimpleRedeclarationDiagnostic extends DiagnosticWithPsiElementImpl<PsiElement> implements RedeclarationDiagnostic {
 
-        public SimpleRedeclarationDiagnostic(@NotNull PsiElement psiElement, @NotNull String name) {
+        public SimpleRedeclarationDiagnostic(@NotNull PsiElement psiElement, @NotNull String name, RedeclarationDiagnosticFactory factory) {
-            super(RedeclarationDiagnosticFactory.INSTANCE, ERROR, "Redeclaration: " + name, psiElement);
+            super(factory, factory.severity, factory.makeMessage(name), psiElement);
         }
     }
 
@@ -24,11 +24,13 @@ public interface RedeclarationDiagnostic extends DiagnosticWithPsiElement<PsiEle
         
         private final DeclarationDescriptor duplicatingDescriptor;
         private final BindingContext contextToResolveToDeclaration;
+        private final RedeclarationDiagnosticFactory factory;
         private PsiElement element;
 
-        public RedeclarationDiagnosticWithDeferredResolution(@NotNull DeclarationDescriptor duplicatingDescriptor, @NotNull BindingContext contextToResolveToDeclaration) {
+        public RedeclarationDiagnosticWithDeferredResolution(@NotNull DeclarationDescriptor duplicatingDescriptor, @NotNull BindingContext contextToResolveToDeclaration, RedeclarationDiagnosticFactory factory) {
             this.duplicatingDescriptor = duplicatingDescriptor;
             this.contextToResolveToDeclaration = contextToResolveToDeclaration;
+            this.factory = factory;
         }
 
         private PsiElement resolve() {
@@ -60,19 +62,19 @@ public interface RedeclarationDiagnostic extends DiagnosticWithPsiElement<PsiEle
         @NotNull
         @Override
         public DiagnosticFactory getFactory() {
-            return Errors.REDECLARATION;
+            return factory;
         }
 
         @NotNull
         @Override
         public String getMessage() {
-            return "Redeclaration: " + duplicatingDescriptor.getName();
+            return factory.makeMessage(duplicatingDescriptor.getName());
         }
 
         @NotNull
         @Override
         public Severity getSeverity() {
-            return ERROR;
+            return factory.severity;
         }
 
         @Override

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

@@ -12,16 +12,27 @@ import org.jetbrains.jet.lang.resolve.BindingContext;
 */
 public class RedeclarationDiagnosticFactory extends AbstractDiagnosticFactory {
     
-    public static final RedeclarationDiagnosticFactory INSTANCE = new RedeclarationDiagnosticFactory();
+    private final String name;
+    final Severity severity;
+    private final String messagePrefix;
 
-    public RedeclarationDiagnosticFactory() {}
+    public static final RedeclarationDiagnosticFactory REDECLARATION = new RedeclarationDiagnosticFactory(
+            "REDECLARATION", Severity.ERROR, "Redeclaration: ");
+    public static final RedeclarationDiagnosticFactory NAME_SHADOWING = new RedeclarationDiagnosticFactory(
+            "NAME_SHADOWING", Severity.WARNING, "Name shadowed: ");
+
+    public RedeclarationDiagnosticFactory(String name, Severity severity, String messagePrefix) {
+        this.name = name;
+        this.severity = severity;
+        this.messagePrefix = messagePrefix;
+    }
 
     public RedeclarationDiagnostic on(@NotNull PsiElement duplicatingElement, @NotNull String name) {
-        return new RedeclarationDiagnostic.SimpleRedeclarationDiagnostic(duplicatingElement, name);
+        return new RedeclarationDiagnostic.SimpleRedeclarationDiagnostic(duplicatingElement, name, this);
     }
 
     public Diagnostic on(DeclarationDescriptor duplicatingDescriptor, BindingContext contextToResolveToDeclaration) {
-        return new RedeclarationDiagnostic.RedeclarationDiagnosticWithDeferredResolution(duplicatingDescriptor, contextToResolveToDeclaration);
+        return new RedeclarationDiagnostic.RedeclarationDiagnosticWithDeferredResolution(duplicatingDescriptor, contextToResolveToDeclaration, this);
     }
 
     @NotNull
@@ -40,7 +51,11 @@ public class RedeclarationDiagnosticFactory extends AbstractDiagnosticFactory {
     @NotNull
     @Override
     public String getName() {
-        return "REDECLARATION";
+        return name;
+    }
+    
+    public String makeMessage(String identifier) {
+        return messagePrefix + identifier;
     }
 
     @Override

compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/ControlStructureTypingVisitor.java

@@ -6,9 +6,12 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.descriptors.FunctionDescriptor;
 import org.jetbrains.jet.lang.descriptors.VariableDescriptor;
+import org.jetbrains.jet.lang.diagnostics.Errors;
 import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.BindingContext;
 import org.jetbrains.jet.lang.resolve.BindingContextUtils;
+import org.jetbrains.jet.lang.resolve.DescriptorUtils;
+import org.jetbrains.jet.lang.resolve.calls.TaskPrioritizers;
 import org.jetbrains.jet.lang.resolve.calls.autocasts.DataFlowInfo;
 import org.jetbrains.jet.lang.resolve.calls.OverloadResolutionResults;
 import org.jetbrains.jet.lang.resolve.scopes.JetScope;
@@ -211,6 +214,16 @@ public class ControlStructureTypingVisitor extends ExpressionTypingVisitor {
                 }
                 variableDescriptor = context.getDescriptorResolver().resolveLocalVariableDescriptor(context.scope.getContainingDeclaration(), loopParameter, expectedParameterType);
             }
+
+            {
+                // http://youtrack.jetbrains.net/issue/KT-527
+
+                VariableDescriptor olderVariable = context.scope.getVariable(variableDescriptor.getName());
+                if (olderVariable != null && DescriptorUtils.isLocal(context.scope.getContainingDeclaration(), olderVariable)) {
+                    context.trace.report(Errors.NAME_SHADOWING.on(variableDescriptor, context.trace.getBindingContext()));
+                }
+            }
+
             loopScope.addVariableDescriptor(variableDescriptor);
         }
 

compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/ExpressionTypingVisitorForStatements.java

@@ -7,6 +7,7 @@ import org.jetbrains.jet.lang.descriptors.*;
 import org.jetbrains.jet.lang.diagnostics.Errors;
 import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.BindingContext;
+import org.jetbrains.jet.lang.resolve.DescriptorUtils;
 import org.jetbrains.jet.lang.resolve.TemporaryBindingTrace;
 import org.jetbrains.jet.lang.resolve.TopDownAnalyzer;
 import org.jetbrains.jet.lang.resolve.calls.CallMaker;
@@ -90,6 +91,13 @@ public class ExpressionTypingVisitorForStatements extends BasicExpressionTypingV
             JetType initializerType = facade.getType(initializer, context.replaceExpectedType(outType).replaceScope(scope));
         }
         
+        {
+            VariableDescriptor olderVariable = scope.getVariable(propertyDescriptor.getName());
+            if (olderVariable != null && DescriptorUtils.isLocal(propertyDescriptor.getContainingDeclaration(), olderVariable)) {
+                context.trace.report(Errors.NAME_SHADOWING.on(propertyDescriptor, context.trace.getBindingContext()));
+            }
+        }
+
         scope.addVariableDescriptor(propertyDescriptor);
         return checkExpectedType(property, context);
     }

compiler/testData/checkerWithErrorTypes/quick/shadowing/ShadowParameterInFunctionBody.jet

@@ -0,0 +1,5 @@
+
+fun f(p: Int): Int {
+    val <!NAME_SHADOWING!>p<!> = 2
+    return p
+}

compiler/testData/checkerWithErrorTypes/quick/shadowing/ShadowParameterInNestedBlockInFor.jet

@@ -0,0 +1,7 @@
+fun f(i: Int) {
+    for (j in 1..100) {
+        {
+            var <!NAME_SHADOWING!>i<!> = 12
+        }
+    }
+}

compiler/testData/checkerWithErrorTypes/quick/shadowing/ShadowPropertyInClosure.jet

@@ -0,0 +1,3 @@
+val i = 17
+
+val f = { (): Int => var i = 17; i }

compiler/testData/checkerWithErrorTypes/quick/shadowing/ShadowPropertyInFor.jet

@@ -0,0 +1,11 @@
+class RedefinePropertyInFor() {
+
+    var i = 1
+    
+    fun ff() {
+        for (i in 0..10) {
+        }
+    }
+
+}
+

compiler/testData/checkerWithErrorTypes/quick/shadowing/ShadowPropertyInFunction.jet

@@ -0,0 +1,10 @@
+class RedefinePropertyInFunction() {
+
+    var i = 17
+    
+    fun f(): Int {
+        var i = 18
+        return i
+    }
+
+}

compiler/testData/checkerWithErrorTypes/quick/shadowing/ShadowVariableInFor.jet

@@ -0,0 +1,6 @@
+fun ff(): Int {
+    var i = 1
+    for (<!NAME_SHADOWING!>i<!> in 0..10) {
+    }
+    return i
+}

compiler/testData/checkerWithErrorTypes/quick/shadowing/ShadowVariableInNestedBlock.jet

@@ -0,0 +1,7 @@
+fun ff(): Int {
+    var i = 1
+    {
+        val <!NAME_SHADOWING!>i<!> = 2
+    }
+    return i
+}

compiler/testData/checkerWithErrorTypes/quick/shadowing/ShadowVariableInNestedClosure.jet

@@ -0,0 +1,5 @@
+fun f(): Int {
+    var i = 17
+    { (): Unit => var <!NAME_SHADOWING!>i<!> = 18 }
+    return i
+}

compiler/testData/checkerWithErrorTypes/quick/shadowing/ShadowVariableInNestedClosureParam.jet

@@ -0,0 +1,5 @@
+fun ff(): Int {
+    var i = 1
+    { (i: Int) => i }
+    return i
+}