Spelling correction

src/compiler/diagnosticMessages.json

@@ -1843,6 +1843,14 @@
         "category": "Error",
         "code": 2550
     },
+    "Property '{0}' does not exist on type '{1}'. Did you mean '{2}'?": {
+        "category": "Error",
+        "code": 2551
+    },
+    "Cannot find name '{0}'. Did you mean '{1}'?": {
+        "category": "Error",
+        "code": 2552
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600
@@ -3532,7 +3540,10 @@
         "category": "Message",
         "code": 90021
     },
-
+    "Change spelling to '{0}'.": {
+        "category": "Message",
+        "code": 90022
+    },
 
     "Octal literal types must use ES2015 syntax. Use the syntax '{0}'.": {
         "category": "Error",

src/compiler/types.ts

@@ -2545,6 +2545,8 @@ namespace ts {
 
         tryGetMemberInModuleExports(memberName: string, moduleSymbol: Symbol): Symbol | undefined;
         getApparentType(type: Type): Type;
+        getSuggestionForNonexistentProperty(node: Identifier, containingType: Type): string | undefined;
+        getSuggestionForNonexistentSymbol(location: Node, name: string, meaning: SymbolFlags): string;
 
         /* @internal */ tryFindAmbientModuleWithoutAugmentations(moduleName: string): Symbol;
 

src/compiler/utilities.ts

@@ -4629,4 +4629,27 @@ namespace ts {
     export function unescapeIdentifier(identifier: string): string {
         return identifier.length >= 3 && identifier.charCodeAt(0) === CharacterCodes._ && identifier.charCodeAt(1) === CharacterCodes._ && identifier.charCodeAt(2) === CharacterCodes._ ? identifier.substr(1) : identifier;
     }
+
+    export function levenshtein(s1: string, s2: string): number {
+        let previous: number[] = new Array(s2.length + 1);
+        let current: number[] = new Array(s2.length + 1);
+        for (let i = 0; i < s2.length + 1; i++) {
+            previous[i] = i;
+            current[i] = -1;
+        }
+        for (let i = 1; i < s1.length + 1; i++) {
+            current[0] = i;
+            for (let j = 1; j < s2.length + 1; j++) {
+                current[j] = Math.min(
+                    previous[j] + 1,
+                    current[j - 1] + 1,
+                    previous[j - 1] + (s1[i - 1] === s2[j - 1] ? 0 : 2));
+            }
+            // shift current back to previous, and then reuse previous' array
+            const tmp = previous;
+            previous = current;
+            current = tmp;
+        }
+        return previous[previous.length - 1];
+    }
 }

src/services/codefixes/fixAddMissingMember.ts

@@ -1,7 +1,8 @@
 /* @internal */
 namespace ts.codefix {
     registerCodeFix({
-        errorCodes: [Diagnostics.Property_0_does_not_exist_on_type_1.code],
+        errorCodes: [Diagnostics.Property_0_does_not_exist_on_type_1.code,
+                     Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_2.code],
         getCodeActions: getActionsForAddMissingMember
     });
 
@@ -135,4 +136,4 @@ namespace ts.codefix {
             return actions;
         }
     }
-}
+}

src/services/codefixes/fixSpelling.ts

@@ -0,0 +1,53 @@
+/* @internal */
+namespace ts.codefix {
+    registerCodeFix({
+        errorCodes: [Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_2.code,
+                     Diagnostics.Cannot_find_name_0_Did_you_mean_1.code],
+        getCodeActions: getActionsForCorrectSpelling
+    });
+
+    function getActionsForCorrectSpelling(context: CodeFixContext): CodeAction[] | undefined {
+        const sourceFile = context.sourceFile;
+
+        // This is the identifier of the misspelled word. eg:
+        // this.speling = 1;
+        //      ^^^^^^^
+        const node = getTokenAtPosition(sourceFile, context.span.start);
+        const checker = context.program.getTypeChecker();
+        let suggestion: string;
+        if (node.kind === SyntaxKind.Identifier && isPropertyAccessExpression(node.parent)) {
+            const containingType = checker.getTypeAtLocation(node.parent.expression);
+            suggestion = checker.getSuggestionForNonexistentProperty(node as Identifier, containingType);
+        }
+        else {
+            const meaning = getMeaningFromLocation(node);
+            suggestion = checker.getSuggestionForNonexistentSymbol(node, getTextOfNode(node), convertSemanticMeaningToSymbolFlags(meaning));
+        }
+        if (suggestion) {
+            return [{
+                description: formatStringFromArgs(getLocaleSpecificMessage(Diagnostics.Change_spelling_to_0), [suggestion]),
+                changes: [{
+                    fileName: sourceFile.fileName,
+                    textChanges: [{
+                        span: { start: node.getStart(), length: node.getWidth() },
+                        newText: suggestion
+                    }],
+                }],
+            }];
+        }
+    }
+
+    function convertSemanticMeaningToSymbolFlags(meaning: SemanticMeaning): SymbolFlags {
+        let flags = 0;
+        if (meaning & SemanticMeaning.Namespace) {
+            flags |= SymbolFlags.Namespace;
+        }
+        if (meaning & SemanticMeaning.Type) {
+            flags |= SymbolFlags.Type;
+        }
+        if (meaning & SemanticMeaning.Value) {
+            flags |= SymbolFlags.Value;
+        }
+        return flags;
+    }
+}

src/services/codefixes/fixes.ts

@@ -1,5 +1,6 @@
 /// <reference path="fixClassIncorrectlyImplementsInterface.ts" />
 /// <reference path="fixAddMissingMember.ts" />
+/// <reference path="fixSpelling.ts" />
 /// <reference path="fixClassDoesntImplementInheritedAbstractMember.ts" />
 /// <reference path="fixClassSuperMustPrecedeThisAccess.ts" />
 /// <reference path="fixConstructorForDerivedNeedSuperCall.ts" />

src/services/codefixes/importFixes.ts

@@ -116,6 +116,7 @@ namespace ts.codefix {
     registerCodeFix({
         errorCodes: [
             Diagnostics.Cannot_find_name_0.code,
+            Diagnostics.Cannot_find_name_0_Did_you_mean_1.code,
             Diagnostics.Cannot_find_namespace_0.code,
             Diagnostics._0_refers_to_a_UMD_global_but_the_current_file_is_a_module_Consider_adding_an_import_instead.code
         ],

src/services/tsconfig.json

@@ -82,6 +82,7 @@
         "formatting/tokenRange.ts",
         "codeFixProvider.ts",
         "codefixes/fixAddMissingMember.ts",
+        "codefixes/fixSpelling.ts",
         "codefixes/fixExtendsInterfaceBecomesImplements.ts",
         "codefixes/fixClassIncorrectlyImplementsInterface.ts",
         "codefixes/fixClassDoesntImplementInheritedAbstractMember.ts",
@@ -94,4 +95,4 @@
         "codefixes/unusedIdentifierFixes.ts",
         "codefixes/disableJsDiagnostics.ts"
     ]
-}
+}

tests/baselines/reference/ModuleWithExportedAndNonExportedFunctions.errors.txt

@@ -1,5 +1,5 @@
-tests/cases/conformance/internalModules/exportDeclarations/ModuleWithExportedAndNonExportedFunctions.ts(28,13): error TS2339: Property 'fn2' does not exist on type 'typeof A'.
-tests/cases/conformance/internalModules/exportDeclarations/ModuleWithExportedAndNonExportedFunctions.ts(29,14): error TS2339: Property 'fng2' does not exist on type 'typeof A'.
+tests/cases/conformance/internalModules/exportDeclarations/ModuleWithExportedAndNonExportedFunctions.ts(28,13): error TS2551: Property 'fn2' does not exist on type 'typeof A'. Did you mean 'fng'?
+tests/cases/conformance/internalModules/exportDeclarations/ModuleWithExportedAndNonExportedFunctions.ts(29,14): error TS2551: Property 'fng2' does not exist on type 'typeof A'. Did you mean 'fng'?
 
 
 ==== tests/cases/conformance/internalModules/exportDeclarations/ModuleWithExportedAndNonExportedFunctions.ts (2 errors) ====
@@ -32,7 +32,7 @@ tests/cases/conformance/internalModules/exportDeclarations/ModuleWithExportedAnd
     // these should be errors since the functions are not exported
     var fn2 = A.fn2;
                 ~~~
-!!! error TS2339: Property 'fn2' does not exist on type 'typeof A'.
+!!! error TS2551: Property 'fn2' does not exist on type 'typeof A'. Did you mean 'fng'?
     var fng2 = A.fng2;
                  ~~~~
-!!! error TS2339: Property 'fng2' does not exist on type 'typeof A'.
+!!! error TS2551: Property 'fng2' does not exist on type 'typeof A'. Did you mean 'fng'?

tests/baselines/reference/VariableDeclaration11_es6.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/conformance/es6/variableDeclarations/VariableDeclaration11_es6.ts(2,1): error TS1212: Identifier expected. 'let' is a reserved word in strict mode.
-tests/cases/conformance/es6/variableDeclarations/VariableDeclaration11_es6.ts(2,1): error TS2304: Cannot find name 'let'.
+tests/cases/conformance/es6/variableDeclarations/VariableDeclaration11_es6.ts(2,1): error TS2552: Cannot find name 'let'. Did you mean 'Set'?
 
 
 ==== tests/cases/conformance/es6/variableDeclarations/VariableDeclaration11_es6.ts (2 errors) ====
@@ -8,4 +8,4 @@ tests/cases/conformance/es6/variableDeclarations/VariableDeclaration11_es6.ts(2,
     ~~~
 !!! error TS1212: Identifier expected. 'let' is a reserved word in strict mode.
     ~~~
-!!! error TS2304: Cannot find name 'let'.
+!!! error TS2552: Cannot find name 'let'. Did you mean 'Set'?

tests/baselines/reference/VariableDeclaration6_es6.errors.txt

@@ -1,7 +1,7 @@
-tests/cases/conformance/es6/variableDeclarations/VariableDeclaration6_es6.ts(1,1): error TS2304: Cannot find name 'let'.
+tests/cases/conformance/es6/variableDeclarations/VariableDeclaration6_es6.ts(1,1): error TS2552: Cannot find name 'let'. Did you mean 'Set'?
 
 
 ==== tests/cases/conformance/es6/variableDeclarations/VariableDeclaration6_es6.ts (1 errors) ====
     let
     ~~~
-!!! error TS2304: Cannot find name 'let'.
+!!! error TS2552: Cannot find name 'let'. Did you mean 'Set'?

tests/baselines/reference/anonymousClassExpression2.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/anonymousClassExpression2.ts(13,18): error TS2339: Property 'methodA' does not exist on type 'B'.
+tests/cases/compiler/anonymousClassExpression2.ts(13,18): error TS2551: Property 'methodA' does not exist on type 'B'. Did you mean 'methodB'?
 
 
 ==== tests/cases/compiler/anonymousClassExpression2.ts (1 errors) ====
@@ -16,7 +16,7 @@ tests/cases/compiler/anonymousClassExpression2.ts(13,18): error TS2339: Property
             methodB() {
                 this.methodA; // error
                      ~~~~~~~
-!!! error TS2339: Property 'methodA' does not exist on type 'B'.
+!!! error TS2551: Property 'methodA' does not exist on type 'B'. Did you mean 'methodB'?
                 this.methodB; // ok
             }
         }

tests/baselines/reference/assignmentRestElementWithErrorSourceType.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/compiler/assignmentRestElementWithErrorSourceType.ts(2,5): error TS2304: Cannot find name 'c'.
-tests/cases/compiler/assignmentRestElementWithErrorSourceType.ts(2,10): error TS2304: Cannot find name 'tupel'.
+tests/cases/compiler/assignmentRestElementWithErrorSourceType.ts(2,10): error TS2552: Cannot find name 'tupel'. Did you mean 'tuple'?
 
 
 ==== tests/cases/compiler/assignmentRestElementWithErrorSourceType.ts (2 errors) ====
@@ -8,4 +8,4 @@ tests/cases/compiler/assignmentRestElementWithErrorSourceType.ts(2,10): error TS
         ~
 !!! error TS2304: Cannot find name 'c'.
              ~~~~~
-!!! error TS2304: Cannot find name 'tupel'.
+!!! error TS2552: Cannot find name 'tupel'. Did you mean 'tuple'?

tests/baselines/reference/autoLift2.errors.txt

@@ -1,13 +1,13 @@
 tests/cases/compiler/autoLift2.ts(5,14): error TS2339: Property 'foo' does not exist on type 'A'.
 tests/cases/compiler/autoLift2.ts(5,17): error TS1005: ';' expected.
-tests/cases/compiler/autoLift2.ts(5,19): error TS2304: Cannot find name 'any'.
-tests/cases/compiler/autoLift2.ts(6,14): error TS2339: Property 'bar' does not exist on type 'A'.
+tests/cases/compiler/autoLift2.ts(5,19): error TS2552: Cannot find name 'any'. Did you mean 'NaN'?
+tests/cases/compiler/autoLift2.ts(6,14): error TS2551: Property 'bar' does not exist on type 'A'. Did you mean 'baz'?
 tests/cases/compiler/autoLift2.ts(6,17): error TS1005: ';' expected.
-tests/cases/compiler/autoLift2.ts(6,19): error TS2304: Cannot find name 'any'.
+tests/cases/compiler/autoLift2.ts(6,19): error TS2552: Cannot find name 'any'. Did you mean 'NaN'?
 tests/cases/compiler/autoLift2.ts(12,11): error TS2339: Property 'foo' does not exist on type 'A'.
-tests/cases/compiler/autoLift2.ts(14,11): error TS2339: Property 'bar' does not exist on type 'A'.
+tests/cases/compiler/autoLift2.ts(14,11): error TS2551: Property 'bar' does not exist on type 'A'. Did you mean 'baz'?
 tests/cases/compiler/autoLift2.ts(16,33): error TS2339: Property 'foo' does not exist on type 'A'.
-tests/cases/compiler/autoLift2.ts(18,33): error TS2339: Property 'bar' does not exist on type 'A'.
+tests/cases/compiler/autoLift2.ts(18,33): error TS2551: Property 'bar' does not exist on type 'A'. Did you mean 'baz'?
 
 
 ==== tests/cases/compiler/autoLift2.ts (10 errors) ====
@@ -21,14 +21,14 @@ tests/cases/compiler/autoLift2.ts(18,33): error TS2339: Property 'bar' does not
                     ~
 !!! error TS1005: ';' expected.
                       ~~~
-!!! error TS2304: Cannot find name 'any'.
+!!! error TS2552: Cannot find name 'any'. Did you mean 'NaN'?
             this.bar: any;
                  ~~~
-!!! error TS2339: Property 'bar' does not exist on type 'A'.
+!!! error TS2551: Property 'bar' does not exist on type 'A'. Did you mean 'baz'?
                     ~
 !!! error TS1005: ';' expected.
                       ~~~
-!!! error TS2304: Cannot find name 'any'.
+!!! error TS2552: Cannot find name 'any'. Did you mean 'NaN'?
         }
 
 
@@ -40,15 +40,15 @@ tests/cases/compiler/autoLift2.ts(18,33): error TS2339: Property 'bar' does not
 
          this.bar = "bar";
               ~~~
-!!! error TS2339: Property 'bar' does not exist on type 'A'.
+!!! error TS2551: Property 'bar' does not exist on type 'A'. Did you mean 'baz'?
 
          [1, 2].forEach((p) => this.foo);
                                     ~~~
 !!! error TS2339: Property 'foo' does not exist on type 'A'.
 
          [1, 2].forEach((p) => this.bar);
                                     ~~~
-!!! error TS2339: Property 'bar' does not exist on type 'A'.
+!!! error TS2551: Property 'bar' does not exist on type 'A'. Did you mean 'baz'?
 
       }
 

tests/baselines/reference/badArrayIndex.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/compiler/badArrayIndex.ts(1,15): error TS2304: Cannot find name 'number'.
+tests/cases/compiler/badArrayIndex.ts(1,15): error TS2552: Cannot find name 'number'. Did you mean 'Number'?
 tests/cases/compiler/badArrayIndex.ts(1,22): error TS1109: Expression expected.
 
 
 ==== tests/cases/compiler/badArrayIndex.ts (2 errors) ====
     var results = number[];
                   ~~~~~~
-!!! error TS2304: Cannot find name 'number'.
+!!! error TS2552: Cannot find name 'number'. Did you mean 'Number'?
                          ~
 !!! error TS1109: Expression expected.

tests/baselines/reference/baseCheck.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/baseCheck.ts(9,18): error TS2304: Cannot find name 'loc'.
+tests/cases/compiler/baseCheck.ts(9,18): error TS2552: Cannot find name 'loc'. Did you mean 'ELoc'?
 tests/cases/compiler/baseCheck.ts(17,53): error TS2346: Supplied parameters do not match any signature of call target.
 tests/cases/compiler/baseCheck.ts(17,59): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 tests/cases/compiler/baseCheck.ts(18,62): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
@@ -20,7 +20,7 @@ tests/cases/compiler/baseCheck.ts(26,9): error TS2304: Cannot find name 'x'.
         constructor(x: number) {
             super(0, loc);
                      ~~~
-!!! error TS2304: Cannot find name 'loc'.
+!!! error TS2552: Cannot find name 'loc'. Did you mean 'ELoc'?
         }
 
         m() {

tests/baselines/reference/bases.errors.txt

@@ -1,13 +1,13 @@
 tests/cases/compiler/bases.ts(7,14): error TS2339: Property 'y' does not exist on type 'B'.
 tests/cases/compiler/bases.ts(7,15): error TS1005: ';' expected.
-tests/cases/compiler/bases.ts(7,17): error TS2304: Cannot find name 'any'.
+tests/cases/compiler/bases.ts(7,17): error TS2552: Cannot find name 'any'. Did you mean 'NaN'?
 tests/cases/compiler/bases.ts(11,7): error TS2420: Class 'C' incorrectly implements interface 'I'.
   Property 'x' is missing in type 'C'.
 tests/cases/compiler/bases.ts(12,5): error TS2377: Constructors for derived classes must contain a 'super' call.
 tests/cases/compiler/bases.ts(13,9): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 tests/cases/compiler/bases.ts(13,14): error TS2339: Property 'x' does not exist on type 'C'.
 tests/cases/compiler/bases.ts(13,15): error TS1005: ';' expected.
-tests/cases/compiler/bases.ts(13,17): error TS2304: Cannot find name 'any'.
+tests/cases/compiler/bases.ts(13,17): error TS2552: Cannot find name 'any'. Did you mean 'NaN'?
 tests/cases/compiler/bases.ts(17,9): error TS2339: Property 'x' does not exist on type 'C'.
 tests/cases/compiler/bases.ts(18,9): error TS2339: Property 'y' does not exist on type 'C'.
 
@@ -25,7 +25,7 @@ tests/cases/compiler/bases.ts(18,9): error TS2339: Property 'y' does not exist o
                   ~
 !!! error TS1005: ';' expected.
                     ~~~
-!!! error TS2304: Cannot find name 'any'.
+!!! error TS2552: Cannot find name 'any'. Did you mean 'NaN'?
         }
     }
 
@@ -44,7 +44,7 @@ tests/cases/compiler/bases.ts(18,9): error TS2339: Property 'y' does not exist o
                   ~
 !!! error TS1005: ';' expected.
                     ~~~
-!!! error TS2304: Cannot find name 'any'.
+!!! error TS2552: Cannot find name 'any'. Did you mean 'NaN'?
         }
     ~~~~~
 !!! error TS2377: Constructors for derived classes must contain a 'super' call.

tests/baselines/reference/breakInIterationOrSwitchStatement4.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/compiler/breakInIterationOrSwitchStatement4.ts(1,15): error TS2304: Cannot find name 'something'.
+tests/cases/compiler/breakInIterationOrSwitchStatement4.ts(1,15): error TS2552: Cannot find name 'something'. Did you mean 'String'?
 
 
 ==== tests/cases/compiler/breakInIterationOrSwitchStatement4.ts (1 errors) ====
     for (var i in something) {
                   ~~~~~~~~~
-!!! error TS2304: Cannot find name 'something'.
+!!! error TS2552: Cannot find name 'something'. Did you mean 'String'?
       break;
     }

tests/baselines/reference/cannotInvokeNewOnIndexExpression.errors.txt

@@ -1,7 +1,7 @@
-tests/cases/compiler/cannotInvokeNewOnIndexExpression.ts(1,23): error TS2304: Cannot find name 'any'.
+tests/cases/compiler/cannotInvokeNewOnIndexExpression.ts(1,23): error TS2552: Cannot find name 'any'. Did you mean 'NaN'?
 
 
 ==== tests/cases/compiler/cannotInvokeNewOnIndexExpression.ts (1 errors) ====
     var test: any[] = new any[1];
                           ~~~
-!!! error TS2304: Cannot find name 'any'.
+!!! error TS2552: Cannot find name 'any'. Did you mean 'NaN'?

tests/baselines/reference/checkJsxChildrenProperty4.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/jsx/file.tsx(24,28): error TS2339: Property 'NAme' does not exist on type 'IUser'.
+tests/cases/conformance/jsx/file.tsx(24,28): error TS2551: Property 'NAme' does not exist on type 'IUser'. Did you mean 'Name'?
 tests/cases/conformance/jsx/file.tsx(32,9): error TS2322: Type '{ children: ((user: IUser) => Element)[]; }' is not assignable to type 'IntrinsicAttributes & IntrinsicClassAttributes<FetchUser> & IFetchUserProps & { children?: ReactNode; }'.
   Type '{ children: ((user: IUser) => Element)[]; }' is not assignable to type 'IFetchUserProps'.
     Types of property 'children' are incompatible.
@@ -32,7 +32,7 @@ tests/cases/conformance/jsx/file.tsx(32,9): error TS2322: Type '{ children: ((us
                 { user => (
                     <h1>{ user.NAme }</h1>
                                ~~~~
-!!! error TS2339: Property 'NAme' does not exist on type 'IUser'.
+!!! error TS2551: Property 'NAme' does not exist on type 'IUser'. Did you mean 'Name'?
                 ) }
             </FetchUser>
         );