microsoft
diff --git a/‎src/compiler/checker.ts
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+170-48Lines changed: 170 additions & 48 deletions b/‎src/compiler/checker.ts
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+170-48Lines changed: 170 additions & 48 deletions
diff --git a/‎src/compiler/diagnosticMessages.json
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+12-1Lines changed: 12 additions & 1 deletion b/‎src/compiler/diagnosticMessages.json
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+12-1Lines changed: 12 additions & 1 deletion
diff --git a/‎src/compiler/types.ts
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+2Lines changed: 2 additions & 0 deletions b/‎src/compiler/types.ts
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+2Lines changed: 2 additions & 0 deletions
diff --git a/‎src/compiler/utilities.ts
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+23Lines changed: 23 additions & 0 deletions b/‎src/compiler/utilities.ts
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+23Lines changed: 23 additions & 0 deletions
diff --git a/‎src/services/codefixes/fixAddMissingMember.ts
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+3-2Lines changed: 3 additions & 2 deletions b/‎src/services/codefixes/fixAddMissingMember.ts
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+3-2Lines changed: 3 additions & 2 deletions
diff --git a/‎src/services/codefixes/fixSpelling.ts
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+53Lines changed: 53 additions & 0 deletions b/‎src/services/codefixes/fixSpelling.ts
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+53Lines changed: 53 additions & 0 deletions
diff --git a/‎src/services/codefixes/fixes.ts
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+1Lines changed: 1 addition & 0 deletions b/‎src/services/codefixes/fixes.ts
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+1Lines changed: 1 addition & 0 deletions
diff --git a/‎src/services/codefixes/importFixes.ts
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+1Lines changed: 1 addition & 0 deletions b/‎src/services/codefixes/importFixes.ts
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+1Lines changed: 1 addition & 0 deletions
diff --git a/‎src/services/tsconfig.json
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+2-1Lines changed: 2 additions & 1 deletion b/‎src/services/tsconfig.json
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+2-1Lines changed: 2 additions & 1 deletion
diff --git a/‎tests/baselines/reference/ModuleWithExportedAndNonExportedFunctions.errors.txt
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+2-2Lines changed: 2 additions & 2 deletions b/‎tests/baselines/reference/ModuleWithExportedAndNonExportedFunctions.errors.txt
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+2-2Lines changed: 2 additions & 2 deletions
@@ -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
@@ -3539,7 +3547,10 @@
         "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",
 
@@ -2552,6 +2552,8 @@ 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 */ getBaseConstraintOfType(type: Type): Type;
 
         /* @internal */ tryFindAmbientModuleWithoutAugmentations(moduleName: string): Symbol;
 
@@ -4641,4 +4641,27 @@ 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];
+    }
 }
@@ -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;
         }
     }
-}
+}
@@ -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;
+    }
+}
@@ -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" />
 
@@ -3,6 +3,7 @@ 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
         ],
 
@@ -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"
     ]
-}
+}
@@ -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(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) ====
@@ -35,4 +35,4 @@ tests/cases/conformance/internalModules/exportDeclarations/ModuleWithExportedAnd
 !!! error TS2339: Property 'fn2' does not exist on type 'typeof A'.
     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'?
Original file line number	Diff line number	Diff line change
`@@ -1,7 +1,8 @@`
`1`	`1`	`/* @internal */`
`2`	`2`	`namespace ts.codefix {`
`3`	`3`	`registerCodeFix({`
`4`		`- errorCodes: [Diagnostics.Property_0_does_not_exist_on_type_1.code],`
	`4`	`+ errorCodes: [Diagnostics.Property_0_does_not_exist_on_type_1.code,`
	`5`	`+ Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_2.code],`
`5`	`6`	`getCodeActions: getActionsForAddMissingMember`
`6`	`7`	`});`
`7`	`8`
`@@ -135,4 +136,4 @@ namespace ts.codefix {`
`135`	`136`	`return actions;`
`136`	`137`	`}`
`137`	`138`	`}`
`138`		`-}`
	`139`	`+}`