diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 7f19737004813..3f071569e9315 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4635,6 +4635,10 @@ namespace ts {
             if (isTypeAny(parentType)) {
                 return parentType;
             }
+            // Relax null check on ambient destructuring parameters, since the parameters have no implementation and are just documentation
+            if (strictNullChecks && declaration.flags & NodeFlags.Ambient && isParameterDeclaration(declaration)) {
+                parentType = getNonNullableType(parentType);
+            }
 
             let type: Type | undefined;
             if (pattern.kind === SyntaxKind.ObjectBindingPattern) {
@@ -4654,53 +4658,13 @@ namespace ts {
                 else {
                     // Use explicitly specified property name ({ p: xxx } form), or otherwise the implied name ({ p } form)
                     const name = declaration.propertyName || <Identifier>declaration.name;
-                    const isLate = isLateBindableName(name);
-                    const isWellKnown = isComputedPropertyName(name) && isWellKnownSymbolSyntactically(name.expression);
-                    if (!isLate && !isWellKnown && isComputedNonLiteralName(name)) {
-                        const exprType = checkExpression((name as ComputedPropertyName).expression);
-                        if (isTypeAssignableToKind(exprType, TypeFlags.ESSymbolLike)) {
-                            if (noImplicitAny) {
-                                error(declaration, Diagnostics.Type_0_cannot_be_used_to_index_type_1, typeToString(exprType), typeToString(parentType));
-                            }
-                            return anyType;
-                        }
-                        const indexerType = isTypeAssignableToKind(exprType, TypeFlags.NumberLike) && getIndexTypeOfType(parentType, IndexKind.Number) || getIndexTypeOfType(parentType, IndexKind.String);
-                        if (!indexerType && noImplicitAny && !compilerOptions.suppressImplicitAnyIndexErrors) {
-                            if (getIndexTypeOfType(parentType, IndexKind.Number)) {
-                                error(declaration, Diagnostics.Element_implicitly_has_an_any_type_because_index_expression_is_not_of_type_number);
-                            }
-                            else {
-                                error(declaration, Diagnostics.Element_implicitly_has_an_any_type_because_type_0_has_no_index_signature, typeToString(parentType));
-                            }
-                        }
-                        return indexerType || anyType;
-                    }
-
-                    // Use type of the specified property, or otherwise, for a numeric name, the type of the numeric index signature,
-                    // or otherwise the type of the string index signature.
-                    const nameType = isLate ? checkComputedPropertyName(name as ComputedPropertyName) as LiteralType | UniqueESSymbolType : undefined;
-                    const text = isLate ? getLateBoundNameFromType(nameType!) :
-                        isWellKnown ? getPropertyNameForKnownSymbolName(idText(((name as ComputedPropertyName).expression as PropertyAccessExpression).name)) :
-                        getTextOfPropertyName(name);
-
-                    // Relax null check on ambient destructuring parameters, since the parameters have no implementation and are just documentation
-                    if (strictNullChecks && declaration.flags & NodeFlags.Ambient && isParameterDeclaration(declaration)) {
-                        parentType = getNonNullableType(parentType);
-                    }
-                    if (isLate && nameType && !getPropertyOfType(parentType, text) && isTypeAssignableToKind(nameType, TypeFlags.ESSymbolLike)) {
-                        if (noImplicitAny) {
-                            error(declaration, Diagnostics.Type_0_cannot_be_used_to_index_type_1, typeToString(nameType), typeToString(parentType));
-                        }
-                        return anyType;
-                    }
-                    const declaredType = getConstraintForLocation(getTypeOfPropertyOfType(parentType, text), declaration.name);
-                    type = declaredType && getFlowTypeOfReference(declaration, declaredType) ||
-                        isNumericLiteralName(text) && getIndexTypeOfType(parentType, IndexKind.Number) ||
-                        getIndexTypeOfType(parentType, IndexKind.String);
-                    if (!type) {
-                        error(name, Diagnostics.Type_0_has_no_property_1_and_no_string_index_signature, typeToString(parentType), declarationNameToString(name));
-                        return errorType;
-                    }
+                    const exprType = isComputedPropertyName(name)
+                        ? checkComputedPropertyName(name)
+                        : isIdentifier(name)
+                            ? getLiteralType(unescapeLeadingUnderscores(name.escapedText))
+                            : checkExpression(name);
+                    const declaredType = checkIndexedAccessIndexType(getIndexedAccessType(getApparentType(parentType), exprType, name), name);
+                    type = getFlowTypeOfReference(declaration, getConstraintForLocation(declaredType, declaration.name));
                 }
             }
             else {
@@ -9359,12 +9323,16 @@ namespace ts {
             return false;
         }
 
-        function getPropertyTypeForIndexType(objectType: Type, indexType: Type, accessNode: ElementAccessExpression | IndexedAccessTypeNode | undefined, cacheSymbol: boolean, missingType: Type) {
+        function getPropertyTypeForIndexType(objectType: Type, indexType: Type, accessNode: ElementAccessExpression | IndexedAccessTypeNode | PropertyName | undefined, cacheSymbol: boolean, missingType: Type) {
             const accessExpression = accessNode && accessNode.kind === SyntaxKind.ElementAccessExpression ? accessNode : undefined;
-            const propName = isTypeUsableAsLateBoundName(indexType) ? getLateBoundNameFromType(indexType) :
-                accessExpression && checkThatExpressionIsProperSymbolReference(accessExpression.argumentExpression, indexType, /*reportError*/ false) ?
-                    getPropertyNameForKnownSymbolName(idText((<PropertyAccessExpression>accessExpression.argumentExpression).name)) :
-                    undefined;
+            const propName = isTypeUsableAsLateBoundName(indexType)
+                ? getLateBoundNameFromType(indexType)
+                : accessExpression && checkThatExpressionIsProperSymbolReference(accessExpression.argumentExpression, indexType, /*reportError*/ false)
+                    ? getPropertyNameForKnownSymbolName(idText((<PropertyAccessExpression>accessExpression.argumentExpression).name))
+                    : accessNode && isPropertyName(accessNode)
+                        // late bound names are handled in the first branch, so here we only need to handle normal names
+                        ? getPropertyNameForPropertyNameNode(accessNode)
+                        : undefined;
             if (propName !== undefined) {
                 const prop = getPropertyOfType(objectType, propName);
                 if (prop) {
@@ -9385,7 +9353,7 @@ namespace ts {
                 }
                 if (everyType(objectType, isTupleType) && isNumericLiteralName(propName) && +propName >= 0) {
                     if (accessNode && everyType(objectType, t => !(<TupleTypeReference>t).target.hasRestElement)) {
-                        const indexNode = accessNode.kind === SyntaxKind.ElementAccessExpression ? accessNode.argumentExpression : accessNode.indexType;
+                        const indexNode = getIndexNodeForAccessExpression(accessNode);
                         error(indexNode, Diagnostics.Property_0_does_not_exist_on_type_1, unescapeLeadingUnderscores(propName), typeToString(objectType));
                     }
                     return mapType(objectType, t => getRestTypeOfTupleType(<TupleTypeReference>t) || undefinedType);
@@ -9400,7 +9368,7 @@ namespace ts {
                     undefined;
                 if (indexInfo) {
                     if (accessNode && !isTypeAssignableToKind(indexType, TypeFlags.String | TypeFlags.Number)) {
-                        const indexNode = accessNode.kind === SyntaxKind.ElementAccessExpression ? accessNode.argumentExpression : accessNode.indexType;
+                        const indexNode = getIndexNodeForAccessExpression(accessNode);
                         error(indexNode, Diagnostics.Type_0_cannot_be_used_as_an_index_type, typeToString(indexType));
                     }
                     else if (accessExpression && indexInfo.isReadonly && (isAssignmentTarget(accessExpression) || isDeleteTarget(accessExpression))) {
@@ -9441,7 +9409,7 @@ namespace ts {
                 return anyType;
             }
             if (accessNode) {
-                const indexNode = accessNode.kind === SyntaxKind.ElementAccessExpression ? accessNode.argumentExpression : accessNode.indexType;
+                const indexNode = getIndexNodeForAccessExpression(accessNode);
                 if (indexType.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) {
                     error(indexNode, Diagnostics.Property_0_does_not_exist_on_type_1, "" + (<LiteralType>indexType).value, typeToString(objectType));
                 }
@@ -9458,6 +9426,16 @@ namespace ts {
             return missingType;
         }
 
+        function getIndexNodeForAccessExpression(accessNode: ElementAccessExpression | IndexedAccessTypeNode | PropertyName) {
+            return accessNode.kind === SyntaxKind.ElementAccessExpression
+            ? accessNode.argumentExpression
+            : accessNode.kind === SyntaxKind.IndexedAccessType
+                ? accessNode.indexType
+                : accessNode.kind === SyntaxKind.ComputedPropertyName
+                    ? accessNode.expression
+                    : accessNode;
+        }
+
         function isGenericObjectType(type: Type): boolean {
             return maybeTypeOfKind(type, TypeFlags.InstantiableNonPrimitive | TypeFlags.GenericMappedType);
         }
@@ -9521,7 +9499,7 @@ namespace ts {
             return instantiateType(getTemplateTypeFromMappedType(objectType), templateMapper);
         }
 
-        function getIndexedAccessType(objectType: Type, indexType: Type, accessNode?: ElementAccessExpression | IndexedAccessTypeNode, missingType = accessNode ? errorType : unknownType): Type {
+        function getIndexedAccessType(objectType: Type, indexType: Type, accessNode?: ElementAccessExpression | IndexedAccessTypeNode | PropertyName, missingType = accessNode ? errorType : unknownType): Type {
             if (objectType === wildcardType || indexType === wildcardType) {
                 return wildcardType;
             }
@@ -23205,7 +23183,7 @@ namespace ts {
             forEach(node.types, checkSourceElement);
         }
 
-        function checkIndexedAccessIndexType(type: Type, accessNode: ElementAccessExpression | IndexedAccessTypeNode) {
+        function checkIndexedAccessIndexType(type: Type, accessNode: Node) {
             if (!(type.flags & TypeFlags.IndexedAccess)) {
                 return type;
             }
diff --git a/tests/baselines/reference/ES5For-of27.errors.txt b/tests/baselines/reference/ES5For-of27.errors.txt
index 0c83985993069..837a11cf7ee89 100644
--- a/tests/baselines/reference/ES5For-of27.errors.txt
+++ b/tests/baselines/reference/ES5For-of27.errors.txt
@@ -1,13 +1,13 @@
-tests/cases/conformance/statements/for-ofStatements/ES5For-of27.ts(1,11): error TS2459: Type 'number' has no property 'x' and no string index signature.
-tests/cases/conformance/statements/for-ofStatements/ES5For-of27.ts(1,21): error TS2459: Type 'number' has no property 'y' and no string index signature.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of27.ts(1,11): error TS2339: Property 'x' does not exist on type 'Number'.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of27.ts(1,21): error TS2339: Property 'y' does not exist on type 'Number'.
 
 
 ==== tests/cases/conformance/statements/for-ofStatements/ES5For-of27.ts (2 errors) ====
     for (var {x: a = 0, y: b = 1} of [2, 3]) {
               ~
-!!! error TS2459: Type 'number' has no property 'x' and no string index signature.
+!!! error TS2339: Property 'x' does not exist on type 'Number'.
                         ~
-!!! error TS2459: Type 'number' has no property 'y' and no string index signature.
+!!! error TS2339: Property 'y' does not exist on type 'Number'.
         a;
         b;
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/ES5For-of29.errors.txt b/tests/baselines/reference/ES5For-of29.errors.txt
index e669b070222e1..c23ff1af21171 100644
--- a/tests/baselines/reference/ES5For-of29.errors.txt
+++ b/tests/baselines/reference/ES5For-of29.errors.txt
@@ -1,13 +1,13 @@
-tests/cases/conformance/statements/for-ofStatements/ES5For-of29.ts(1,13): error TS2459: Type 'number' has no property 'x' and no string index signature.
-tests/cases/conformance/statements/for-ofStatements/ES5For-of29.ts(1,23): error TS2459: Type 'number' has no property 'y' and no string index signature.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of29.ts(1,13): error TS2339: Property 'x' does not exist on type 'Number'.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of29.ts(1,23): error TS2339: Property 'y' does not exist on type 'Number'.
 
 
 ==== tests/cases/conformance/statements/for-ofStatements/ES5For-of29.ts (2 errors) ====
     for (const {x: a = 0, y: b = 1} of [2, 3]) {
                 ~
-!!! error TS2459: Type 'number' has no property 'x' and no string index signature.
+!!! error TS2339: Property 'x' does not exist on type 'Number'.
                           ~
-!!! error TS2459: Type 'number' has no property 'y' and no string index signature.
+!!! error TS2339: Property 'y' does not exist on type 'Number'.
         a;
         b;
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/ES5For-of35.errors.txt b/tests/baselines/reference/ES5For-of35.errors.txt
index 8c43d9598888d..c22dc96e42dce 100644
--- a/tests/baselines/reference/ES5For-of35.errors.txt
+++ b/tests/baselines/reference/ES5For-of35.errors.txt
@@ -1,13 +1,13 @@
-tests/cases/conformance/statements/for-ofStatements/ES5For-of35.ts(1,13): error TS2459: Type 'number' has no property 'x' and no string index signature.
-tests/cases/conformance/statements/for-ofStatements/ES5For-of35.ts(1,23): error TS2459: Type 'number' has no property 'y' and no string index signature.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of35.ts(1,13): error TS2339: Property 'x' does not exist on type 'Number'.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of35.ts(1,23): error TS2339: Property 'y' does not exist on type 'Number'.
 
 
 ==== tests/cases/conformance/statements/for-ofStatements/ES5For-of35.ts (2 errors) ====
     for (const {x: a = 0, y: b = 1} of [2, 3]) {
                 ~
-!!! error TS2459: Type 'number' has no property 'x' and no string index signature.
+!!! error TS2339: Property 'x' does not exist on type 'Number'.
                           ~
-!!! error TS2459: Type 'number' has no property 'y' and no string index signature.
+!!! error TS2339: Property 'y' does not exist on type 'Number'.
         a;
         b;
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/blockScopedBindingUsedBeforeDef.errors.txt b/tests/baselines/reference/blockScopedBindingUsedBeforeDef.errors.txt
index 042f5e6de4fc7..4f04f2babc5d5 100644
--- a/tests/baselines/reference/blockScopedBindingUsedBeforeDef.errors.txt
+++ b/tests/baselines/reference/blockScopedBindingUsedBeforeDef.errors.txt
@@ -1,23 +1,32 @@
 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts(2,12): error TS2448: Block-scoped variable 'a' used before its declaration.
+tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts(2,12): error TS2538: Type 'any' cannot be used as an index type.
 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts(5,12): error TS2448: Block-scoped variable 'a' used before its declaration.
+tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts(5,12): error TS2538: Type 'any' cannot be used as an index type.
 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts(8,7): error TS2448: Block-scoped variable 'b' used before its declaration.
+tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts(8,7): error TS2538: Type 'any' cannot be used as an index type.
 
 
-==== tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts (3 errors) ====
+==== tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts (6 errors) ====
     // 1:
     for (let {[a]: a} of [{ }]) continue;
                ~
 !!! error TS2448: Block-scoped variable 'a' used before its declaration.
 !!! related TS2728 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts:2:16: 'a' is declared here.
+               ~
+!!! error TS2538: Type 'any' cannot be used as an index type.
     
     // 2:
     for (let {[a]: a} = { }; false; ) continue;
                ~
 !!! error TS2448: Block-scoped variable 'a' used before its declaration.
 !!! related TS2728 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts:5:16: 'a' is declared here.
+               ~
+!!! error TS2538: Type 'any' cannot be used as an index type.
     
     // 3:
     let {[b]: b} = { };
           ~
 !!! error TS2448: Block-scoped variable 'b' used before its declaration.
-!!! related TS2728 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts:8:11: 'b' is declared here.
\ No newline at end of file
+!!! related TS2728 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts:8:11: 'b' is declared here.
+          ~
+!!! error TS2538: Type 'any' cannot be used as an index type.
\ No newline at end of file
diff --git a/tests/baselines/reference/computedPropertiesInDestructuring1.errors.txt b/tests/baselines/reference/computedPropertiesInDestructuring1.errors.txt
index d2d63a4817498..31b938fb3fb3e 100644
--- a/tests/baselines/reference/computedPropertiesInDestructuring1.errors.txt
+++ b/tests/baselines/reference/computedPropertiesInDestructuring1.errors.txt
@@ -1,33 +1,63 @@
+tests/cases/compiler/computedPropertiesInDestructuring1.ts(3,7): error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1.ts(8,7): error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1.ts(10,8): error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1.ts(11,8): error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1.ts(14,15): error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1.ts(15,15): error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1.ts(16,16): error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1.ts(17,16): error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
 tests/cases/compiler/computedPropertiesInDestructuring1.ts(20,8): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type 'String' has no compatible call signatures.
+tests/cases/compiler/computedPropertiesInDestructuring1.ts(20,8): error TS2538: Type 'any' cannot be used as an index type.
+tests/cases/compiler/computedPropertiesInDestructuring1.ts(21,8): error TS2538: Type 'any' cannot be used as an index type.
 tests/cases/compiler/computedPropertiesInDestructuring1.ts(21,12): error TS2339: Property 'toExponential' does not exist on type 'string'.
 tests/cases/compiler/computedPropertiesInDestructuring1.ts(33,4): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type 'String' has no compatible call signatures.
 tests/cases/compiler/computedPropertiesInDestructuring1.ts(34,5): error TS2365: Operator '+' cannot be applied to types '1' and '{}'.
 
 
-==== tests/cases/compiler/computedPropertiesInDestructuring1.ts (4 errors) ====
+==== tests/cases/compiler/computedPropertiesInDestructuring1.ts (14 errors) ====
     // destructuring in variable declarations
     let foo = "bar";
     let {[foo]: bar} = {bar: "bar"};
+          ~~~
+!!! error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
     
     let {["bar"]: bar2} = {bar: "bar"};
     
     let foo2 = () => "bar";
     let {[foo2()]: bar3} = {bar: "bar"};
+          ~~~~~~
+!!! error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
     
     let [{[foo]: bar4}] = [{bar: "bar"}];
+           ~~~
+!!! error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
     let [{[foo2()]: bar5}] = [{bar: "bar"}];
+           ~~~~~~
+!!! error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
     
     function f1({["bar"]: x}: { bar: number }) {}
     function f2({[foo]: x}: { bar: number }) {}
+                  ~~~
+!!! error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
     function f3({[foo2()]: x}: { bar: number }) {}
+                  ~~~~~~
+!!! error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
     function f4([{[foo]: x}]: [{ bar: number }]) {}
+                   ~~~
+!!! error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
     function f5([{[foo2()]: x}]: [{ bar: number }]) {}
+                   ~~~~~~
+!!! error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
     
     // report errors on type errors in computed properties used in destructuring
     let [{[foo()]: bar6}] = [{bar: "bar"}];
            ~~~~~
 !!! error TS2349: Cannot invoke an expression whose type lacks a call signature. Type 'String' has no compatible call signatures.
+           ~~~~~
+!!! error TS2538: Type 'any' cannot be used as an index type.
     let [{[foo.toExponential()]: bar7}] = [{bar: "bar"}];
+           ~~~~~~~~~~~~~~~~~~~
+!!! error TS2538: Type 'any' cannot be used as an index type.
                ~~~~~~~~~~~~~
 !!! error TS2339: Property 'toExponential' does not exist on type 'string'.
     
diff --git a/tests/baselines/reference/computedPropertiesInDestructuring1_ES6.errors.txt b/tests/baselines/reference/computedPropertiesInDestructuring1_ES6.errors.txt
index fa4d29cf42653..610b8e56ab3da 100644
--- a/tests/baselines/reference/computedPropertiesInDestructuring1_ES6.errors.txt
+++ b/tests/baselines/reference/computedPropertiesInDestructuring1_ES6.errors.txt
@@ -1,34 +1,64 @@
+tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(3,7): error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(9,7): error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(11,8): error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(12,8): error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(15,15): error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(16,15): error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(17,16): error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
+tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(18,16): error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
 tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(21,8): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type 'String' has no compatible call signatures.
+tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(21,8): error TS2538: Type 'any' cannot be used as an index type.
+tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(22,8): error TS2538: Type 'any' cannot be used as an index type.
 tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(22,12): error TS2339: Property 'toExponential' does not exist on type 'string'.
 tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(34,4): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type 'String' has no compatible call signatures.
 tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts(35,5): error TS2365: Operator '+' cannot be applied to types '1' and '{}'.
 
 
-==== tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts (4 errors) ====
+==== tests/cases/compiler/computedPropertiesInDestructuring1_ES6.ts (14 errors) ====
     // destructuring in variable declarations
     let foo = "bar";
     let {[foo]: bar} = {bar: "bar"};
+          ~~~
+!!! error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
     
     let {["bar"]: bar2} = {bar: "bar"};
     let {[11]: bar2_1} = {11: "bar"};
     
     let foo2 = () => "bar";
     let {[foo2()]: bar3} = {bar: "bar"};
+          ~~~~~~
+!!! error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
     
     let [{[foo]: bar4}] = [{bar: "bar"}];
+           ~~~
+!!! error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
     let [{[foo2()]: bar5}] = [{bar: "bar"}];
+           ~~~~~~
+!!! error TS2537: Type '{ bar: string; }' has no matching index signature for type 'string'.
     
     function f1({["bar"]: x}: { bar: number }) {}
     function f2({[foo]: x}: { bar: number }) {}
+                  ~~~
+!!! error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
     function f3({[foo2()]: x}: { bar: number }) {}
+                  ~~~~~~
+!!! error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
     function f4([{[foo]: x}]: [{ bar: number }]) {}
+                   ~~~
+!!! error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
     function f5([{[foo2()]: x}]: [{ bar: number }]) {}
+                   ~~~~~~
+!!! error TS2537: Type '{ bar: number; }' has no matching index signature for type 'string'.
     
     // report errors on type errors in computed properties used in destructuring
     let [{[foo()]: bar6}] = [{bar: "bar"}];
            ~~~~~
 !!! error TS2349: Cannot invoke an expression whose type lacks a call signature. Type 'String' has no compatible call signatures.
+           ~~~~~
+!!! error TS2538: Type 'any' cannot be used as an index type.
     let [{[foo.toExponential()]: bar7}] = [{bar: "bar"}];
+           ~~~~~~~~~~~~~~~~~~~
+!!! error TS2538: Type 'any' cannot be used as an index type.
                ~~~~~~~~~~~~~
 !!! error TS2339: Property 'toExponential' does not exist on type 'string'.
     
diff --git a/tests/baselines/reference/computedPropertiesInDestructuring2.errors.txt b/tests/baselines/reference/computedPropertiesInDestructuring2.errors.txt
new file mode 100644
index 0000000000000..da858e47c892d
--- /dev/null
+++ b/tests/baselines/reference/computedPropertiesInDestructuring2.errors.txt
@@ -0,0 +1,8 @@
+tests/cases/compiler/computedPropertiesInDestructuring2.ts(2,7): error TS2537: Type '{}' has no matching index signature for type 'string'.
+
+
+==== tests/cases/compiler/computedPropertiesInDestructuring2.ts (1 errors) ====
+    let foo2 = () => "bar";
+    let {[foo2()]: bar3} = {};
+          ~~~~~~
+!!! error TS2537: Type '{}' has no matching index signature for type 'string'.
\ No newline at end of file
diff --git a/tests/baselines/reference/computedPropertiesInDestructuring2_ES6.errors.txt b/tests/baselines/reference/computedPropertiesInDestructuring2_ES6.errors.txt
new file mode 100644
index 0000000000000..529cc2ebef82a
--- /dev/null
+++ b/tests/baselines/reference/computedPropertiesInDestructuring2_ES6.errors.txt
@@ -0,0 +1,8 @@
+tests/cases/compiler/computedPropertiesInDestructuring2_ES6.ts(2,7): error TS2537: Type '{}' has no matching index signature for type 'string'.
+
+
+==== tests/cases/compiler/computedPropertiesInDestructuring2_ES6.ts (1 errors) ====
+    let foo2 = () => "bar";
+    let {[foo2()]: bar3} = {};
+          ~~~~~~
+!!! error TS2537: Type '{}' has no matching index signature for type 'string'.
\ No newline at end of file
diff --git a/tests/baselines/reference/declarationsAndAssignments.errors.txt b/tests/baselines/reference/declarationsAndAssignments.errors.txt
index 46536d6fff04e..3ae6d587da529 100644
--- a/tests/baselines/reference/declarationsAndAssignments.errors.txt
+++ b/tests/baselines/reference/declarationsAndAssignments.errors.txt
@@ -15,8 +15,8 @@ tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(67,9): e
 tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(68,9): error TS2461: Type '{ 0: number; 1: number; }' is not an array type.
 tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(73,11): error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
 tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(73,14): error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
-tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(74,11): error TS2459: Type 'undefined[]' has no property 'a' and no string index signature.
-tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(74,14): error TS2459: Type 'undefined[]' has no property 'b' and no string index signature.
+tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(74,11): error TS2339: Property 'a' does not exist on type 'undefined[]'.
+tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(74,14): error TS2339: Property 'b' does not exist on type 'undefined[]'.
 tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(106,17): error TS2322: Type '{ y: boolean; }' is not assignable to type '{ x: any; y?: boolean; }'.
   Property 'x' is missing in type '{ y: boolean; }'.
 tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(138,6): error TS2322: Type 'string' is not assignable to type 'number'.
@@ -133,9 +133,9 @@ tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(138,9):
 !!! error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
         var { a, b } = [];  // Error
               ~
-!!! error TS2459: Type 'undefined[]' has no property 'a' and no string index signature.
+!!! error TS2339: Property 'a' does not exist on type 'undefined[]'.
                  ~
-!!! error TS2459: Type 'undefined[]' has no property 'b' and no string index signature.
+!!! error TS2339: Property 'b' does not exist on type 'undefined[]'.
     }
     
     function f11() {
diff --git a/tests/baselines/reference/definiteAssignmentOfDestructuredVariable.types b/tests/baselines/reference/definiteAssignmentOfDestructuredVariable.types
index 96d632736dd84..fb40a9b492e6f 100644
--- a/tests/baselines/reference/definiteAssignmentOfDestructuredVariable.types
+++ b/tests/baselines/reference/definiteAssignmentOfDestructuredVariable.types
@@ -18,20 +18,20 @@ class C<T extends Options> {
 >method : () => void
 
         let { a, b } = this.foo;
->a : T["a"]
->b : T["b"]
+>a : { [P in keyof T]: T[P]; }["a"]
+>b : { [P in keyof T]: T[P]; }["b"]
 >this.foo : { [P in keyof T]: T[P]; }
 >this : this
 >foo : { [P in keyof T]: T[P]; }
 
         !(a && b);
 >!(a && b) : false
->(a && b) : T["b"]
->a && b : T["b"]
->a : T["a"]
->b : T["b"]
+>(a && b) : { [P in keyof T]: T[P]; }["b"]
+>a && b : { [P in keyof T]: T[P]; }["b"]
+>a : { [P in keyof T]: T[P]; }["a"]
+>b : { [P in keyof T]: T[P]; }["b"]
 
         a;
->a : T["a"]
+>a : { [P in keyof T]: T[P]; }["a"]
     }
 }
diff --git a/tests/baselines/reference/destructuredLateBoundNameHasCorrectTypes.errors.txt b/tests/baselines/reference/destructuredLateBoundNameHasCorrectTypes.errors.txt
index 6a5c50021db04..100ce2d9a0879 100644
--- a/tests/baselines/reference/destructuredLateBoundNameHasCorrectTypes.errors.txt
+++ b/tests/baselines/reference/destructuredLateBoundNameHasCorrectTypes.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/destructuredLateBoundNameHasCorrectTypes.ts(11,7): error TS2459: Type '{ prop: string; }' has no property '[notPresent]' and no string index signature.
+tests/cases/compiler/destructuredLateBoundNameHasCorrectTypes.ts(11,8): error TS2339: Property 'prop2' does not exist on type '{ prop: string; }'.
 
 
 ==== tests/cases/compiler/destructuredLateBoundNameHasCorrectTypes.ts (1 errors) ====
@@ -13,6 +13,6 @@ tests/cases/compiler/destructuredLateBoundNameHasCorrectTypes.ts(11,7): error TS
     const notPresent = "prop2";
     
     let { [notPresent]: computed2 } = { prop: "b" };
-          ~~~~~~~~~~~~
-!!! error TS2459: Type '{ prop: string; }' has no property '[notPresent]' and no string index signature.
+           ~~~~~~~~~~
+!!! error TS2339: Property 'prop2' does not exist on type '{ prop: string; }'.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/destructuredMaappedTypeIsNotImplicitlyAny.js b/tests/baselines/reference/destructuredMaappedTypeIsNotImplicitlyAny.js
new file mode 100644
index 0000000000000..3fe1f2febcc26
--- /dev/null
+++ b/tests/baselines/reference/destructuredMaappedTypeIsNotImplicitlyAny.js
@@ -0,0 +1,16 @@
+//// [destructuredMaappedTypeIsNotImplicitlyAny.ts]
+function foo<T extends string>(key: T, obj: { [_ in T]: number }) {
+    const { [key]: bar } = obj; // Element implicitly has an 'any' type because type '{ [_ in T]: number; }' has no index signature.
+    bar; // bar : any
+
+    // Note: this does work:
+    const lorem = obj[key];
+}
+
+//// [destructuredMaappedTypeIsNotImplicitlyAny.js]
+function foo(key, obj) {
+    var _a = key, bar = obj[_a]; // Element implicitly has an 'any' type because type '{ [_ in T]: number; }' has no index signature.
+    bar; // bar : any
+    // Note: this does work:
+    var lorem = obj[key];
+}
diff --git a/tests/baselines/reference/destructuredMaappedTypeIsNotImplicitlyAny.symbols b/tests/baselines/reference/destructuredMaappedTypeIsNotImplicitlyAny.symbols
new file mode 100644
index 0000000000000..93bd2be6638b4
--- /dev/null
+++ b/tests/baselines/reference/destructuredMaappedTypeIsNotImplicitlyAny.symbols
@@ -0,0 +1,24 @@
+=== tests/cases/compiler/destructuredMaappedTypeIsNotImplicitlyAny.ts ===
+function foo<T extends string>(key: T, obj: { [_ in T]: number }) {
+>foo : Symbol(foo, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 0, 0))
+>T : Symbol(T, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 0, 13))
+>key : Symbol(key, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 0, 31))
+>T : Symbol(T, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 0, 13))
+>obj : Symbol(obj, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 0, 38))
+>_ : Symbol(_, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 0, 47))
+>T : Symbol(T, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 0, 13))
+
+    const { [key]: bar } = obj; // Element implicitly has an 'any' type because type '{ [_ in T]: number; }' has no index signature.
+>key : Symbol(key, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 0, 31))
+>bar : Symbol(bar, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 1, 11))
+>obj : Symbol(obj, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 0, 38))
+
+    bar; // bar : any
+>bar : Symbol(bar, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 1, 11))
+
+    // Note: this does work:
+    const lorem = obj[key];
+>lorem : Symbol(lorem, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 5, 9))
+>obj : Symbol(obj, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 0, 38))
+>key : Symbol(key, Decl(destructuredMaappedTypeIsNotImplicitlyAny.ts, 0, 31))
+}
diff --git a/tests/baselines/reference/destructuredMaappedTypeIsNotImplicitlyAny.types b/tests/baselines/reference/destructuredMaappedTypeIsNotImplicitlyAny.types
new file mode 100644
index 0000000000000..493eabe1e2a28
--- /dev/null
+++ b/tests/baselines/reference/destructuredMaappedTypeIsNotImplicitlyAny.types
@@ -0,0 +1,21 @@
+=== tests/cases/compiler/destructuredMaappedTypeIsNotImplicitlyAny.ts ===
+function foo<T extends string>(key: T, obj: { [_ in T]: number }) {
+>foo : <T extends string>(key: T, obj: { [_ in T]: number; }) => void
+>key : T
+>obj : { [_ in T]: number; }
+
+    const { [key]: bar } = obj; // Element implicitly has an 'any' type because type '{ [_ in T]: number; }' has no index signature.
+>key : T
+>bar : { [_ in T]: number; }[T]
+>obj : { [_ in T]: number; }
+
+    bar; // bar : any
+>bar : { [_ in T]: number; }[T]
+
+    // Note: this does work:
+    const lorem = obj[key];
+>lorem : { [_ in T]: number; }[T]
+>obj[key] : { [_ in T]: number; }[T]
+>obj : { [_ in T]: number; }
+>key : T
+}
diff --git a/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.errors.txt b/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.errors.txt
index 33344b9b5eb00..5a906d7d43e5e 100644
--- a/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.errors.txt
+++ b/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.errors.txt
@@ -1,8 +1,8 @@
 tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(2,7): error TS1005: ',' expected.
 tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(3,5): error TS2322: Type '{ i: number; }' is not assignable to type 'string | number'.
   Type '{ i: number; }' is not assignable to type 'number'.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(3,6): error TS2459: Type 'string | number' has no property 'i' and no string index signature.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(4,6): error TS2459: Type 'string | number | {}' has no property 'i1' and no string index signature.
+tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(3,6): error TS2339: Property 'i' does not exist on type 'string | number'.
+tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(4,6): error TS2339: Property 'i1' does not exist on type 'string | number | {}'.
 tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(5,12): error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
 tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(5,21): error TS2353: Object literal may only specify known properties, and 'f212' does not exist in type '{ f21: any; }'.
 tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(6,7): error TS1005: ':' expected.
@@ -20,10 +20,10 @@ tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAs
 !!! error TS2322: Type '{ i: number; }' is not assignable to type 'string | number'.
 !!! error TS2322:   Type '{ i: number; }' is not assignable to type 'number'.
          ~
-!!! error TS2459: Type 'string | number' has no property 'i' and no string index signature.
+!!! error TS2339: Property 'i' does not exist on type 'string | number'.
     var {i1}: string | number| {} = { i1: 2 };
          ~~
-!!! error TS2459: Type 'string | number | {}' has no property 'i1' and no string index signature.
+!!! error TS2339: Property 'i1' does not exist on type 'string | number | {}'.
     var { f2: {f21} = { f212: "string" } }: any = undefined;
                ~~~
 !!! error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
diff --git a/tests/baselines/reference/destructuringParameterProperties5.errors.txt b/tests/baselines/reference/destructuringParameterProperties5.errors.txt
index 44e013fad0bd2..fa57ae150a053 100644
--- a/tests/baselines/reference/destructuringParameterProperties5.errors.txt
+++ b/tests/baselines/reference/destructuringParameterProperties5.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/conformance/es6/destructuring/destructuringParameterProperties5.ts(5,17): error TS1187: A parameter property may not be declared using a binding pattern.
-tests/cases/conformance/es6/destructuring/destructuringParameterProperties5.ts(5,27): error TS2459: Type 'ObjType1' has no property 'x1' and no string index signature.
-tests/cases/conformance/es6/destructuring/destructuringParameterProperties5.ts(5,31): error TS2459: Type 'ObjType1' has no property 'x2' and no string index signature.
-tests/cases/conformance/es6/destructuring/destructuringParameterProperties5.ts(5,35): error TS2459: Type 'ObjType1' has no property 'x3' and no string index signature.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties5.ts(5,27): error TS2339: Property 'x1' does not exist on type 'ObjType1'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties5.ts(5,31): error TS2339: Property 'x2' does not exist on type 'ObjType1'.
+tests/cases/conformance/es6/destructuring/destructuringParameterProperties5.ts(5,35): error TS2339: Property 'x3' does not exist on type 'ObjType1'.
 tests/cases/conformance/es6/destructuring/destructuringParameterProperties5.ts(7,29): error TS2339: Property 'x1' does not exist on type 'C1'.
 tests/cases/conformance/es6/destructuring/destructuringParameterProperties5.ts(7,40): error TS2339: Property 'x2' does not exist on type 'C1'.
 tests/cases/conformance/es6/destructuring/destructuringParameterProperties5.ts(7,51): error TS2339: Property 'x3' does not exist on type 'C1'.
@@ -22,11 +22,11 @@ tests/cases/conformance/es6/destructuring/destructuringParameterProperties5.ts(1
                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS1187: A parameter property may not be declared using a binding pattern.
                               ~~
-!!! error TS2459: Type 'ObjType1' has no property 'x1' and no string index signature.
+!!! error TS2339: Property 'x1' does not exist on type 'ObjType1'.
                                   ~~
-!!! error TS2459: Type 'ObjType1' has no property 'x2' and no string index signature.
+!!! error TS2339: Property 'x2' does not exist on type 'ObjType1'.
                                       ~~
-!!! error TS2459: Type 'ObjType1' has no property 'x3' and no string index signature.
+!!! error TS2339: Property 'x3' does not exist on type 'ObjType1'.
             var foo: any = x1 || x2 || x3 || y || z;
             var bar: any = this.x1 || this.x2 || this.x3 || this.y || this.z;
                                 ~~
diff --git a/tests/baselines/reference/downlevelLetConst16.errors.txt b/tests/baselines/reference/downlevelLetConst16.errors.txt
index 905d1a607e81d..955c79378fe30 100644
--- a/tests/baselines/reference/downlevelLetConst16.errors.txt
+++ b/tests/baselines/reference/downlevelLetConst16.errors.txt
@@ -1,9 +1,9 @@
 tests/cases/compiler/downlevelLetConst16.ts(151,15): error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
 tests/cases/compiler/downlevelLetConst16.ts(164,17): error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
 tests/cases/compiler/downlevelLetConst16.ts(195,14): error TS2461: Type 'undefined' is not an array type.
-tests/cases/compiler/downlevelLetConst16.ts(202,15): error TS2459: Type 'undefined' has no property 'a' and no string index signature.
+tests/cases/compiler/downlevelLetConst16.ts(202,15): error TS2339: Property 'a' does not exist on type 'undefined'.
 tests/cases/compiler/downlevelLetConst16.ts(216,16): error TS2461: Type 'undefined' is not an array type.
-tests/cases/compiler/downlevelLetConst16.ts(223,17): error TS2459: Type 'undefined' has no property 'a' and no string index signature.
+tests/cases/compiler/downlevelLetConst16.ts(223,17): error TS2339: Property 'a' does not exist on type 'undefined'.
 
 
 ==== tests/cases/compiler/downlevelLetConst16.ts (6 errors) ====
@@ -216,7 +216,7 @@ tests/cases/compiler/downlevelLetConst16.ts(223,17): error TS2459: Type 'undefin
     function foo9() {
         for (let {a: x} of []) {
                   ~
-!!! error TS2459: Type 'undefined' has no property 'a' and no string index signature.
+!!! error TS2339: Property 'a' does not exist on type 'undefined'.
             use(x);
         }
         use(x);
@@ -241,7 +241,7 @@ tests/cases/compiler/downlevelLetConst16.ts(223,17): error TS2459: Type 'undefin
     function foo12() {
         for (const {a: x} of []) {
                     ~
-!!! error TS2459: Type 'undefined' has no property 'a' and no string index signature.
+!!! error TS2339: Property 'a' does not exist on type 'undefined'.
             use(x);
         }
         use(x);
diff --git a/tests/baselines/reference/for-inStatementsDestructuring2.errors.txt b/tests/baselines/reference/for-inStatementsDestructuring2.errors.txt
index 7589610a64e35..5d80cf26ebc2c 100644
--- a/tests/baselines/reference/for-inStatementsDestructuring2.errors.txt
+++ b/tests/baselines/reference/for-inStatementsDestructuring2.errors.txt
@@ -1,6 +1,6 @@
 tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring2.ts(1,10): error TS2491: The left-hand side of a 'for...in' statement cannot be a destructuring pattern.
-tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring2.ts(1,11): error TS2459: Type 'string' has no property 'a' and no string index signature.
-tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring2.ts(1,14): error TS2459: Type 'string' has no property 'b' and no string index signature.
+tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring2.ts(1,11): error TS2339: Property 'a' does not exist on type 'String'.
+tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring2.ts(1,14): error TS2339: Property 'b' does not exist on type 'String'.
 
 
 ==== tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructuring2.ts (3 errors) ====
@@ -8,6 +8,6 @@ tests/cases/conformance/statements/for-inStatements/for-inStatementsDestructurin
              ~~~~~~
 !!! error TS2491: The left-hand side of a 'for...in' statement cannot be a destructuring pattern.
               ~
-!!! error TS2459: Type 'string' has no property 'a' and no string index signature.
+!!! error TS2339: Property 'a' does not exist on type 'String'.
                  ~
-!!! error TS2459: Type 'string' has no property 'b' and no string index signature.
\ No newline at end of file
+!!! error TS2339: Property 'b' does not exist on type 'String'.
\ No newline at end of file
diff --git a/tests/baselines/reference/jsdocParamTag2.errors.txt b/tests/baselines/reference/jsdocParamTag2.errors.txt
index e19140b3f9deb..cbf6140ee7d86 100644
--- a/tests/baselines/reference/jsdocParamTag2.errors.txt
+++ b/tests/baselines/reference/jsdocParamTag2.errors.txt
@@ -1,6 +1,6 @@
 tests/cases/conformance/jsdoc/0.js(56,20): error TS8024: JSDoc '@param' tag has name 'obj', but there is no parameter with that name.
-tests/cases/conformance/jsdoc/0.js(61,19): error TS2459: Type 'string' has no property 'a' and no string index signature.
-tests/cases/conformance/jsdoc/0.js(61,22): error TS2459: Type 'string' has no property 'b' and no string index signature.
+tests/cases/conformance/jsdoc/0.js(61,19): error TS2339: Property 'a' does not exist on type 'String'.
+tests/cases/conformance/jsdoc/0.js(61,22): error TS2339: Property 'b' does not exist on type 'String'.
 tests/cases/conformance/jsdoc/0.js(63,20): error TS8024: JSDoc '@param' tag has name 'y', but there is no parameter with that name.
 
 
@@ -69,9 +69,9 @@ tests/cases/conformance/jsdoc/0.js(63,20): error TS8024: JSDoc '@param' tag has
      */
     function bad1(x, {a, b}) {}
                       ~
-!!! error TS2459: Type 'string' has no property 'a' and no string index signature.
+!!! error TS2339: Property 'a' does not exist on type 'String'.
                          ~
-!!! error TS2459: Type 'string' has no property 'b' and no string index signature.
+!!! error TS2339: Property 'b' does not exist on type 'String'.
     /**
      * @param {string} y - here, y's type gets ignored but obj's is fine
                        ~
diff --git a/tests/baselines/reference/lateBoundDestructuringImplicitAnyError.errors.txt b/tests/baselines/reference/lateBoundDestructuringImplicitAnyError.errors.txt
index 2e926ac1b83d3..edba02d293927 100644
--- a/tests/baselines/reference/lateBoundDestructuringImplicitAnyError.errors.txt
+++ b/tests/baselines/reference/lateBoundDestructuringImplicitAnyError.errors.txt
@@ -1,16 +1,16 @@
-tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(2,15): error TS7017: Element implicitly has an 'any' type because type '{ prop: string; }' has no index signature.
-tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(13,15): error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
-tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(21,15): error TS2536: Type 'unique symbol' cannot be used to index type '{ [idx: number]: string; }'.
-tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(23,15): error TS2536: Type 'unique symbol' cannot be used to index type '{ [idx: string]: string; }'.
-tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(25,16): error TS2536: Type 'symbol' cannot be used to index type '{ [idx: number]: string; }'.
-tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(27,16): error TS2536: Type 'symbol' cannot be used to index type '{ [idx: string]: string; }'.
+tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(2,7): error TS2537: Type '{ prop: string; }' has no matching index signature for type 'string'.
+tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(13,7): error TS2537: Type '{ [idx: number]: string; }' has no matching index signature for type 'string'.
+tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(21,7): error TS2538: Type 'unique symbol' cannot be used as an index type.
+tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(23,7): error TS2538: Type 'unique symbol' cannot be used as an index type.
+tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(25,7): error TS2538: Type 'symbol' cannot be used as an index type.
+tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(27,7): error TS2538: Type 'symbol' cannot be used as an index type.
 
 
 ==== tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts (6 errors) ====
     let named = "foo";
     let {[named]: prop} = {prop: "foo"};
-                  ~~~~
-!!! error TS7017: Element implicitly has an 'any' type because type '{ prop: string; }' has no index signature.
+          ~~~~~
+!!! error TS2537: Type '{ prop: string; }' has no matching index signature for type 'string'.
     void prop;
     
     const numIndexed: {[idx: number]: string} = null as any;
@@ -22,8 +22,8 @@ tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(27,16): error TS2
     let symed2 = Symbol();
     
     let {[named]: prop2} = numIndexed;
-                  ~~~~~
-!!! error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
+          ~~~~~
+!!! error TS2537: Type '{ [idx: number]: string; }' has no matching index signature for type 'string'.
     void prop2;
     let {[numed]: prop3} = numIndexed;
     void prop3;
@@ -32,18 +32,18 @@ tests/cases/compiler/lateBoundDestructuringImplicitAnyError.ts(27,16): error TS2
     let {[numed]: prop5} = strIndexed;
     void prop5;
     let {[symed]: prop6} = numIndexed;
-                  ~~~~~
-!!! error TS2536: Type 'unique symbol' cannot be used to index type '{ [idx: number]: string; }'.
+          ~~~~~
+!!! error TS2538: Type 'unique symbol' cannot be used as an index type.
     void prop6;
     let {[symed]: prop7} = strIndexed;
-                  ~~~~~
-!!! error TS2536: Type 'unique symbol' cannot be used to index type '{ [idx: string]: string; }'.
+          ~~~~~
+!!! error TS2538: Type 'unique symbol' cannot be used as an index type.
     void prop7;
     let {[symed2]: prop8} = numIndexed;
-                   ~~~~~
-!!! error TS2536: Type 'symbol' cannot be used to index type '{ [idx: number]: string; }'.
+          ~~~~~~
+!!! error TS2538: Type 'symbol' cannot be used as an index type.
     void prop8;
     let {[symed2]: prop9} = strIndexed;
-                   ~~~~~
-!!! error TS2536: Type 'symbol' cannot be used to index type '{ [idx: string]: string; }'.
+          ~~~~~~
+!!! error TS2538: Type 'symbol' cannot be used as an index type.
     void prop9;
\ No newline at end of file
diff --git a/tests/baselines/reference/lateBoundDestructuringImplicitAnyError.types b/tests/baselines/reference/lateBoundDestructuringImplicitAnyError.types
index 92d2c4c662c4b..60c220095adb3 100644
--- a/tests/baselines/reference/lateBoundDestructuringImplicitAnyError.types
+++ b/tests/baselines/reference/lateBoundDestructuringImplicitAnyError.types
@@ -87,12 +87,12 @@ void prop6;
 
 let {[symed]: prop7} = strIndexed;
 >symed : unique symbol
->prop7 : any
+>prop7 : string
 >strIndexed : { [idx: string]: string; }
 
 void prop7;
 >void prop7 : undefined
->prop7 : any
+>prop7 : string
 
 let {[symed2]: prop8} = numIndexed;
 >symed2 : symbol
@@ -105,10 +105,10 @@ void prop8;
 
 let {[symed2]: prop9} = strIndexed;
 >symed2 : symbol
->prop9 : any
+>prop9 : string
 >strIndexed : { [idx: string]: string; }
 
 void prop9;
 >void prop9 : undefined
->prop9 : any
+>prop9 : string
 
diff --git a/tests/baselines/reference/nonPrimitiveAccessProperty.errors.txt b/tests/baselines/reference/nonPrimitiveAccessProperty.errors.txt
index 0a6dfa66b86b2..c584dba6462f2 100644
--- a/tests/baselines/reference/nonPrimitiveAccessProperty.errors.txt
+++ b/tests/baselines/reference/nonPrimitiveAccessProperty.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/types/nonPrimitive/nonPrimitiveAccessProperty.ts(3,3): error TS2339: Property 'nonExist' does not exist on type 'object'.
-tests/cases/conformance/types/nonPrimitive/nonPrimitiveAccessProperty.ts(5,7): error TS2459: Type 'object' has no property 'destructuring' and no string index signature.
+tests/cases/conformance/types/nonPrimitive/nonPrimitiveAccessProperty.ts(5,7): error TS2339: Property 'destructuring' does not exist on type '{}'.
 
 
 ==== tests/cases/conformance/types/nonPrimitive/nonPrimitiveAccessProperty.ts (2 errors) ====
@@ -11,6 +11,6 @@ tests/cases/conformance/types/nonPrimitive/nonPrimitiveAccessProperty.ts(5,7): e
     
     var { destructuring } = a; // error
           ~~~~~~~~~~~~~
-!!! error TS2459: Type 'object' has no property 'destructuring' and no string index signature.
+!!! error TS2339: Property 'destructuring' does not exist on type '{}'.
     var { ...rest } = a; // ok
     
\ No newline at end of file
diff --git a/tests/baselines/reference/objectRest.errors.txt b/tests/baselines/reference/objectRest.errors.txt
new file mode 100644
index 0000000000000..709a2d3cdd6c7
--- /dev/null
+++ b/tests/baselines/reference/objectRest.errors.txt
@@ -0,0 +1,62 @@
+tests/cases/conformance/types/rest/objectRest.ts(7,12): error TS2339: Property '0' does not exist on type 'String'.
+tests/cases/conformance/types/rest/objectRest.ts(7,20): error TS2339: Property '1' does not exist on type 'String'.
+tests/cases/conformance/types/rest/objectRest.ts(43,8): error TS2537: Type '{ a: number; b: string; }' has no matching index signature for type 'string'.
+tests/cases/conformance/types/rest/objectRest.ts(43,35): error TS2537: Type '{ a: number; b: string; }' has no matching index signature for type 'string'.
+
+
+==== tests/cases/conformance/types/rest/objectRest.ts (4 errors) ====
+    var o = { a: 1, b: 'no' }
+    var { ...clone } = o;
+    var { a, ...justB } = o;
+    var { a, b: renamed, ...empty } = o;
+    var { ['b']: renamed, ...justA } = o;
+    var { 'b': renamed, ...justA } = o;
+    var { b: { '0': n, '1': oooo }, ...justA } = o;
+               ~~~
+!!! error TS2339: Property '0' does not exist on type 'String'.
+                       ~~~
+!!! error TS2339: Property '1' does not exist on type 'String'.
+    
+    let o2 = { c: 'terrible idea?', d: 'yes' };
+    var { d: renamed, ...d } = o2;
+    
+    let nestedrest: { x: number, n1: { y: number, n2: { z: number, n3: { n4: number } } }, rest: number, restrest: number };
+    var { x, n1: { y, n2: { z, n3: { ...nr } } }, ...restrest } = nestedrest;
+    
+    let complex: { x: { ka, ki }, y: number };
+    var { x: { ka, ...nested }, y: other, ...rest } = complex;
+    ({x: { ka, ...nested }, y: other, ...rest} = complex);
+    var { x, ...fresh } = { x: 1, y: 2 };
+    ({ x, ...fresh } = { x: 1, y: 2 });
+    
+    class Removable {
+        private x: number;
+        protected y: number;
+        set z(value: number) { }
+        get both(): number { return 12 }
+        set both(value: number) { }
+        m() { }
+        removed: string;
+        remainder: string;
+    }
+    interface I {
+        m(): void;
+        removed: string;
+        remainder: string;
+    }
+    var removable = new Removable();
+    var { removed, ...removableRest } = removable;
+    var i: I = removable;
+    var { removed, ...removableRest2 } = i;
+    
+    let computed = 'b';
+    let computed2 = 'a';
+    var { [computed]: stillNotGreat, [computed2]: soSo,  ...o } = o;
+           ~~~~~~~~
+!!! error TS2537: Type '{ a: number; b: string; }' has no matching index signature for type 'string'.
+                                      ~~~~~~~~~
+!!! error TS2537: Type '{ a: number; b: string; }' has no matching index signature for type 'string'.
+    ({ [computed]: stillNotGreat, [computed2]: soSo, ...o } = o);
+    
+    var noContextualType = ({ aNumber = 12, ...notEmptyObject }) => aNumber + notEmptyObject.anythingGoes;
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/objectRest.types b/tests/baselines/reference/objectRest.types
index cb50daf9c4b0a..dfce7e47912c0 100644
--- a/tests/baselines/reference/objectRest.types
+++ b/tests/baselines/reference/objectRest.types
@@ -36,8 +36,8 @@ var { 'b': renamed, ...justA } = o;
 
 var { b: { '0': n, '1': oooo }, ...justA } = o;
 >b : any
->n : string
->oooo : string
+>n : any
+>oooo : any
 >justA : { a: number; }
 >o : { a: number; b: string; }
 
diff --git a/tests/baselines/reference/parameterInitializersForwardReferencing1_es6.errors.txt b/tests/baselines/reference/parameterInitializersForwardReferencing1_es6.errors.txt
index 59280d2006a01..c65f327161ebe 100644
--- a/tests/baselines/reference/parameterInitializersForwardReferencing1_es6.errors.txt
+++ b/tests/baselines/reference/parameterInitializersForwardReferencing1_es6.errors.txt
@@ -1,9 +1,10 @@
 tests/cases/conformance/functions/parameterInitializersForwardReferencing1_es6.ts(13,20): error TS2373: Initializer of parameter 'bar' cannot reference identifier 'foo' declared after it.
 tests/cases/conformance/functions/parameterInitializersForwardReferencing1_es6.ts(21,18): error TS2372: Parameter 'a' cannot be referenced in its initializer.
 tests/cases/conformance/functions/parameterInitializersForwardReferencing1_es6.ts(25,22): error TS2372: Parameter 'async' cannot be referenced in its initializer.
+tests/cases/conformance/functions/parameterInitializersForwardReferencing1_es6.ts(29,15): error TS2537: Type 'any[]' has no matching index signature for type 'string'.
 
 
-==== tests/cases/conformance/functions/parameterInitializersForwardReferencing1_es6.ts (3 errors) ====
+==== tests/cases/conformance/functions/parameterInitializersForwardReferencing1_es6.ts (4 errors) ====
     let foo: string = "";
     
     function f1 (bar = foo) { // unexpected compiler error; works at runtime
@@ -39,6 +40,8 @@ tests/cases/conformance/functions/parameterInitializersForwardReferencing1_es6.t
     }
     
     function f7({[foo]: bar}: any[]) {
+                  ~~~
+!!! error TS2537: Type 'any[]' has no matching index signature for type 'string'.
         let foo: number = 2;
     }
     
diff --git a/tests/baselines/reference/restElementWithBindingPattern2.errors.txt b/tests/baselines/reference/restElementWithBindingPattern2.errors.txt
index 8e744ac54a38a..44e2c8f13ed1f 100644
--- a/tests/baselines/reference/restElementWithBindingPattern2.errors.txt
+++ b/tests/baselines/reference/restElementWithBindingPattern2.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/conformance/es6/destructuring/restElementWithBindingPattern2.ts(1,16): error TS2459: Type 'number[]' has no property 'b' and no string index signature.
+tests/cases/conformance/es6/destructuring/restElementWithBindingPattern2.ts(1,16): error TS2339: Property 'b' does not exist on type 'number[]'.
 
 
 ==== tests/cases/conformance/es6/destructuring/restElementWithBindingPattern2.ts (1 errors) ====
     var [...{0: a, b }] = [0, 1];
                    ~
-!!! error TS2459: Type 'number[]' has no property 'b' and no string index signature.
\ No newline at end of file
+!!! error TS2339: Property 'b' does not exist on type 'number[]'.
\ No newline at end of file
diff --git a/tests/cases/compiler/destructuredMaappedTypeIsNotImplicitlyAny.ts b/tests/cases/compiler/destructuredMaappedTypeIsNotImplicitlyAny.ts
new file mode 100644
index 0000000000000..4fd88fd5c8e68
--- /dev/null
+++ b/tests/cases/compiler/destructuredMaappedTypeIsNotImplicitlyAny.ts
@@ -0,0 +1,8 @@
+// @noImplicitAny: true
+function foo<T extends string>(key: T, obj: { [_ in T]: number }) {
+    const { [key]: bar } = obj; // Element implicitly has an 'any' type because type '{ [_ in T]: number; }' has no index signature.
+    bar; // bar : any
+
+    // Note: this does work:
+    const lorem = obj[key];
+}
\ No newline at end of file