diff --git a/src/compiler/builder.ts b/src/compiler/builder.ts
index d4d7327fbd7ee..1882c9d6eab37 100644
--- a/src/compiler/builder.ts
+++ b/src/compiler/builder.ts
@@ -693,7 +693,7 @@ namespace ts {
             const cachedDiagnostics = state.semanticDiagnosticsPerFile.get(path);
             // Report the bind and check diagnostics from the cache if we already have those diagnostics present
             if (cachedDiagnostics) {
-                return filterSemanticDiagnotics(cachedDiagnostics, state.compilerOptions);
+                return filterSemanticDiagnostics(cachedDiagnostics, state.compilerOptions);
             }
         }
 
@@ -702,7 +702,7 @@ namespace ts {
         if (state.semanticDiagnosticsPerFile) {
             state.semanticDiagnosticsPerFile.set(path, diagnostics);
         }
-        return filterSemanticDiagnotics(diagnostics, state.compilerOptions);
+        return filterSemanticDiagnostics(diagnostics, state.compilerOptions);
     }
 
     export type ProgramBuildInfoFileId = number & { __programBuildInfoFileIdBrand: any };
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 38c193758be7a..ea8526ba61464 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -1076,15 +1076,19 @@ namespace ts {
             return diagnostic;
         }
 
-        function error(location: Node | undefined, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number, arg3?: string | number): Diagnostic {
-            const diagnostic = location
+        function createError(location: Node | undefined, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number, arg3?: string | number): Diagnostic {
+            return location
                 ? createDiagnosticForNode(location, message, arg0, arg1, arg2, arg3)
                 : createCompilerDiagnostic(message, arg0, arg1, arg2, arg3);
+        }
+
+        function error(location: Node | undefined, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number, arg3?: string | number): Diagnostic {
+            const diagnostic = createError(location, message, arg0, arg1, arg2, arg3);
             diagnostics.add(diagnostic);
             return diagnostic;
         }
 
-        function addErrorOrSuggestion(isError: boolean, diagnostic: DiagnosticWithLocation) {
+        function addErrorOrSuggestion(isError: boolean, diagnostic: Diagnostic) {
             if (isError) {
                 diagnostics.add(diagnostic);
             }
@@ -1708,8 +1712,8 @@ namespace ts {
             nameArg: __String | Identifier | undefined,
             isUse: boolean,
             excludeGlobals = false,
-            suggestedNameNotFoundMessage?: DiagnosticMessage): Symbol | undefined {
-            return resolveNameHelper(location, name, meaning, nameNotFoundMessage, nameArg, isUse, excludeGlobals, getSymbol, suggestedNameNotFoundMessage);
+            issueSuggestions?: boolean): Symbol | undefined {
+            return resolveNameHelper(location, name, meaning, nameNotFoundMessage, nameArg, isUse, excludeGlobals, getSymbol, issueSuggestions);
         }
 
         function resolveNameHelper(
@@ -1720,8 +1724,7 @@ namespace ts {
             nameArg: __String | Identifier | undefined,
             isUse: boolean,
             excludeGlobals: boolean,
-            lookup: typeof getSymbol,
-            suggestedNameNotFoundMessage?: DiagnosticMessage): Symbol | undefined {
+            lookup: typeof getSymbol, issueSuggestions?: boolean): Symbol | undefined {
             const originalLocation = location; // needed for did-you-mean error reporting, which gathers candidates starting from the original location
             let result: Symbol | undefined;
             let lastLocation: Node | undefined;
@@ -2058,15 +2061,19 @@ namespace ts {
                         !checkAndReportErrorForUsingNamespaceModuleAsValue(errorLocation, name, meaning) &&
                         !checkAndReportErrorForUsingValueAsType(errorLocation, name, meaning)) {
                         let suggestion: Symbol | undefined;
-                        if (suggestedNameNotFoundMessage && suggestionCount < maximumSuggestionCount) {
+                        if (issueSuggestions && suggestionCount < maximumSuggestionCount) {
                             suggestion = getSuggestedSymbolForNonexistentSymbol(originalLocation, name, meaning);
-                            const isGlobalScopeAugmentationDeclaration = suggestion && suggestion.valueDeclaration && isAmbientModule(suggestion.valueDeclaration) && isGlobalScopeAugmentation(suggestion.valueDeclaration);
+                            const isGlobalScopeAugmentationDeclaration = suggestion?.valueDeclaration && isAmbientModule(suggestion.valueDeclaration) && isGlobalScopeAugmentation(suggestion.valueDeclaration);
                             if (isGlobalScopeAugmentationDeclaration) {
                                 suggestion = undefined;
                             }
                             if (suggestion) {
                                 const suggestionName = symbolToString(suggestion);
-                                const diagnostic = error(errorLocation, suggestedNameNotFoundMessage, diagnosticName(nameArg!), suggestionName);
+                                const isUncheckedJS = isUncheckedJSSuggestion(originalLocation, suggestion, /*excludeClasses*/ false);
+                                const message = isUncheckedJS ? Diagnostics.Could_not_find_name_0_Did_you_mean_1 : Diagnostics.Cannot_find_name_0_Did_you_mean_1;
+                                const diagnostic = createError(errorLocation, message, diagnosticName(nameArg!), suggestionName);
+                                addErrorOrSuggestion(!isUncheckedJS, diagnostic);
+
                                 if (suggestion.valueDeclaration) {
                                     addRelatedInfo(
                                         diagnostic,
@@ -21939,7 +21946,7 @@ namespace ts {
                         node,
                         !isWriteOnlyAccess(node),
                         /*excludeGlobals*/ false,
-                        Diagnostics.Cannot_find_name_0_Did_you_mean_1) || unknownSymbol;
+                        /*issueSuggestions*/ true) || unknownSymbol;
             }
             return links.resolvedSymbol;
         }
@@ -27453,7 +27460,8 @@ namespace ts {
             if (!prop) {
                 const indexInfo = !isPrivateIdentifier(right) && (assignmentKind === AssignmentKind.None || !isGenericObjectType(leftType) || isThisTypeParameter(leftType)) ? getIndexInfoOfType(apparentType, IndexKind.String) : undefined;
                 if (!(indexInfo && indexInfo.type)) {
-                    if (isJSLiteralType(leftType)) {
+                    const isUncheckedJS = isUncheckedJSSuggestion(node, leftType.symbol, /*excludeClasses*/ true);
+                    if (!isUncheckedJS && isJSLiteralType(leftType)) {
                         return anyType;
                     }
                     if (leftType.symbol === globalThisSymbol) {
@@ -27466,7 +27474,7 @@ namespace ts {
                         return anyType;
                     }
                     if (right.escapedText && !checkAndReportErrorForExtendingInterface(node)) {
-                        reportNonexistentProperty(right, isThisTypeParameter(leftType) ? apparentType : leftType);
+                        reportNonexistentProperty(right, isThisTypeParameter(leftType) ? apparentType : leftType, isUncheckedJS);
                     }
                     return errorType;
                 }
@@ -27499,6 +27507,26 @@ namespace ts {
             return getFlowTypeOfAccessExpression(node, prop, propType, right, checkMode);
         }
 
+        /**
+         * Determines whether a did-you-mean error should be a suggestion in an unchecked JS file.
+         * Only applies to unchecked JS files without checkJS, // @ts-check or // @ts-nocheck
+         * It does not suggest when the suggestion:
+         * - Is from a global file that is different from the reference file, or
+         * - (optionally) Is a class, or is a this.x property access expression
+         */
+        function isUncheckedJSSuggestion(node: Node | undefined, suggestion: Symbol | undefined, excludeClasses: boolean): boolean {
+            const file = getSourceFileOfNode(node);
+            if (file) {
+                if (compilerOptions.checkJs === undefined && file.checkJsDirective === undefined && (file.scriptKind === ScriptKind.JS || file.scriptKind === ScriptKind.JSX)) {
+                    const declarationFile = forEach(suggestion?.declarations, getSourceFileOfNode);
+                    return !(file !== declarationFile && !!declarationFile && isGlobalSourceFile(declarationFile))
+                        && !(excludeClasses && suggestion && suggestion.flags & SymbolFlags.Class)
+                        && !(!!node && excludeClasses && isPropertyAccessExpression(node) && node.expression.kind === SyntaxKind.ThisKeyword);
+                }
+            }
+            return false;
+        }
+
         function getFlowTypeOfAccessExpression(node: ElementAccessExpression | PropertyAccessExpression | QualifiedName, prop: Symbol | undefined, propType: Type, errorNode: Node, checkMode: CheckMode | undefined) {
             // Only compute control flow type if this is a property access expression that isn't an
             // assignment target, and the referenced property was declared as a variable, property,
@@ -27630,7 +27658,7 @@ namespace ts {
             return getIntersectionType(x);
         }
 
-        function reportNonexistentProperty(propNode: Identifier | PrivateIdentifier, containingType: Type) {
+        function reportNonexistentProperty(propNode: Identifier | PrivateIdentifier, containingType: Type, isUncheckedJS: boolean) {
             let errorInfo: DiagnosticMessageChain | undefined;
             let relatedInfo: Diagnostic | undefined;
             if (!isPrivateIdentifier(propNode) && containingType.flags & TypeFlags.Union && !(containingType.flags & TypeFlags.Primitive)) {
@@ -27663,7 +27691,8 @@ namespace ts {
                         const suggestion = getSuggestedSymbolForNonexistentProperty(propNode, containingType);
                         if (suggestion !== undefined) {
                             const suggestedName = symbolName(suggestion);
-                            errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_2, missingProperty, container, suggestedName);
+                            const message = isUncheckedJS ? Diagnostics.Property_0_may_not_exist_on_type_1_Did_you_mean_2 : Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_2;
+                            errorInfo = chainDiagnosticMessages(errorInfo, message, missingProperty, container, suggestedName);
                             relatedInfo = suggestion.valueDeclaration && createDiagnosticForNode(suggestion.valueDeclaration, Diagnostics._0_is_declared_here, suggestedName);
                         }
                         else {
@@ -27679,7 +27708,7 @@ namespace ts {
             if (relatedInfo) {
                 addRelatedInfo(resultDiagnostic, relatedInfo);
             }
-            diagnostics.add(resultDiagnostic);
+            addErrorOrSuggestion(!isUncheckedJS, resultDiagnostic);
         }
 
         function containerSeemsToBeEmptyDomElement(containingType: Type) {
@@ -34594,7 +34623,7 @@ namespace ts {
 
             const rootName = getFirstIdentifier(typeName);
             const meaning = (typeName.kind === SyntaxKind.Identifier ? SymbolFlags.Type : SymbolFlags.Namespace) | SymbolFlags.Alias;
-            const rootSymbol = resolveName(rootName, rootName.escapedText, meaning, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isRefernce*/ true);
+            const rootSymbol = resolveName(rootName, rootName.escapedText, meaning, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isReference*/ true);
             if (rootSymbol
                 && rootSymbol.flags & SymbolFlags.Alias
                 && symbolIsValue(rootSymbol)
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index d2ddbc8b0a4ec..1e2a0329cb00b 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -2442,10 +2442,18 @@
         "category": "Error",
         "code": 2567
     },
+    "Property '{0}' may not exist on type '{1}'. Did you mean '{2}'?": {
+        "category": "Error",
+        "code": 2568
+    },
     "Type '{0}' is not an array type or a string type. Use compiler option '--downlevelIteration' to allow iterating of iterators.": {
         "category": "Error",
         "code": 2569
     },
+    "Could not find name '{0}'. Did you mean '{1}'?": {
+        "category": "Error",
+        "code": 2570
+    },
     "Object is of type 'unknown'.": {
         "category": "Error",
         "code": 2571
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 91529ceada8d4..440a930983ebe 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1896,7 +1896,7 @@ namespace ts {
 
         function getSemanticDiagnosticsForFile(sourceFile: SourceFile, cancellationToken: CancellationToken | undefined): readonly Diagnostic[] {
             return concatenate(
-                filterSemanticDiagnotics(getBindAndCheckDiagnosticsForFile(sourceFile, cancellationToken), options),
+                filterSemanticDiagnostics(getBindAndCheckDiagnosticsForFile(sourceFile, cancellationToken), options),
                 getProgramDiagnostics(sourceFile)
             );
         }
@@ -1918,8 +1918,8 @@ namespace ts {
                 const isCheckJs = isCheckJsEnabledForFile(sourceFile, options);
                 const isTsNoCheck = !!sourceFile.checkJsDirective && sourceFile.checkJsDirective.enabled === false;
                 // By default, only type-check .ts, .tsx, 'Deferred' and 'External' files (external files are added by plugins)
-                const includeBindAndCheckDiagnostics = !isTsNoCheck && (sourceFile.scriptKind === ScriptKind.TS || sourceFile.scriptKind === ScriptKind.TSX ||
-                    sourceFile.scriptKind === ScriptKind.External || isCheckJs || sourceFile.scriptKind === ScriptKind.Deferred);
+                const includeBindAndCheckDiagnostics = !isTsNoCheck && (sourceFile.scriptKind === ScriptKind.TS || sourceFile.scriptKind === ScriptKind.TSX
+                    || sourceFile.scriptKind === ScriptKind.External || isCheckJs || sourceFile.scriptKind === ScriptKind.Deferred);
                 const bindDiagnostics: readonly Diagnostic[] = includeBindAndCheckDiagnostics ? sourceFile.bindDiagnostics : emptyArray;
                 const checkDiagnostics = includeBindAndCheckDiagnostics ? typeChecker.getDiagnostics(sourceFile, cancellationToken) : emptyArray;
 
@@ -3891,7 +3891,7 @@ namespace ts {
     }
 
     /*@internal*/
-    export function filterSemanticDiagnotics(diagnostic: readonly Diagnostic[], option: CompilerOptions): readonly Diagnostic[] {
+    export function filterSemanticDiagnostics(diagnostic: readonly Diagnostic[], option: CompilerOptions): readonly Diagnostic[] {
         return filter(diagnostic, d => !d.skippedOn || !option[d.skippedOn]);
     }
 
diff --git a/src/services/codefixes/fixSpelling.ts b/src/services/codefixes/fixSpelling.ts
index 6d80e1f900899..2712976d7c6b4 100644
--- a/src/services/codefixes/fixSpelling.ts
+++ b/src/services/codefixes/fixSpelling.ts
@@ -3,7 +3,9 @@ namespace ts.codefix {
     const fixId = "fixSpelling";
     const errorCodes = [
         Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_2.code,
+        Diagnostics.Property_0_may_not_exist_on_type_1_Did_you_mean_2.code,
         Diagnostics.Cannot_find_name_0_Did_you_mean_1.code,
+        Diagnostics.Could_not_find_name_0_Did_you_mean_1.code,
         Diagnostics.Cannot_find_name_0_Did_you_mean_the_instance_member_this_0.code,
         Diagnostics.Cannot_find_name_0_Did_you_mean_the_static_member_1_0.code,
         Diagnostics._0_has_no_exported_member_named_1_Did_you_mean_2.code,
diff --git a/tests/baselines/reference/argumentsReferenceInConstructor3_Js.types b/tests/baselines/reference/argumentsReferenceInConstructor3_Js.types
index ccdf9b660674d..4b6557cd1b972 100644
--- a/tests/baselines/reference/argumentsReferenceInConstructor3_Js.types
+++ b/tests/baselines/reference/argumentsReferenceInConstructor3_Js.types
@@ -43,11 +43,11 @@ class B extends A {
 		 * @type object
 		 */
 		this.bar = super.arguments.foo;
->this.bar = super.arguments.foo : any
+>this.bar = super.arguments.foo : error
 >this.bar : any
 >this : this
 >bar : any
->super.arguments.foo : any
+>super.arguments.foo : error
 >super.arguments : { bar: {}; }
 >super : A
 >arguments : { bar: {}; }
diff --git a/tests/baselines/reference/jsObjectsMarkedAsOpenEnded.types b/tests/baselines/reference/jsObjectsMarkedAsOpenEnded.types
index 777f779e9c78c..adb07b7bae781 100644
--- a/tests/baselines/reference/jsObjectsMarkedAsOpenEnded.types
+++ b/tests/baselines/reference/jsObjectsMarkedAsOpenEnded.types
@@ -27,7 +27,7 @@ class C {
 
         this.member.a = 0;
 >this.member.a = 0 : 0
->this.member.a : any
+>this.member.a : error
 >this.member : {}
 >this : this
 >member : {}
@@ -48,7 +48,7 @@ var obj = {
 
 obj.property.a = 0;
 >obj.property.a = 0 : 0
->obj.property.a : any
+>obj.property.a : error
 >obj.property : {}
 >obj : { property: {}; }
 >property : {}
diff --git a/tests/baselines/reference/spellingUncheckedJS.symbols b/tests/baselines/reference/spellingUncheckedJS.symbols
new file mode 100644
index 0000000000000..59355de95cb92
--- /dev/null
+++ b/tests/baselines/reference/spellingUncheckedJS.symbols
@@ -0,0 +1,95 @@
+=== tests/cases/conformance/salsa/spellingUncheckedJS.js ===
+export var inModule = 1
+>inModule : Symbol(inModule, Decl(spellingUncheckedJS.js, 0, 10))
+
+inmodule.toFixed()
+
+function f() {
+>f : Symbol(f, Decl(spellingUncheckedJS.js, 1, 18))
+
+    var locals = 2 + true
+>locals : Symbol(locals, Decl(spellingUncheckedJS.js, 4, 7))
+
+    locale.toFixed()
+    // @ts-expect-error
+    localf.toExponential()
+    // @ts-expect-error
+    "this is fine"
+}
+class Classe {
+>Classe : Symbol(Classe, Decl(spellingUncheckedJS.js, 10, 1))
+
+    non = 'oui'
+>non : Symbol(Classe.non, Decl(spellingUncheckedJS.js, 11, 14))
+
+    methode() {
+>methode : Symbol(Classe.methode, Decl(spellingUncheckedJS.js, 12, 15))
+
+        // no error on 'this' references
+        return this.none
+>this : Symbol(Classe, Decl(spellingUncheckedJS.js, 10, 1))
+    }
+}
+class Derivee extends Classe {
+>Derivee : Symbol(Derivee, Decl(spellingUncheckedJS.js, 17, 1))
+>Classe : Symbol(Classe, Decl(spellingUncheckedJS.js, 10, 1))
+
+    methode() {
+>methode : Symbol(Derivee.methode, Decl(spellingUncheckedJS.js, 18, 30))
+
+        // no error on 'super' references
+        return super.none
+>super : Symbol(Classe, Decl(spellingUncheckedJS.js, 10, 1))
+    }
+}
+
+
+var object = {
+>object : Symbol(object, Decl(spellingUncheckedJS.js, 26, 3), Decl(spellingUncheckedJS.js, 29, 15), Decl(spellingUncheckedJS.js, 30, 18))
+
+    spaaace: 3
+>spaaace : Symbol(spaaace, Decl(spellingUncheckedJS.js, 26, 14))
+}
+object.spaaaace // error on read
+>object : Symbol(object, Decl(spellingUncheckedJS.js, 26, 3), Decl(spellingUncheckedJS.js, 29, 15), Decl(spellingUncheckedJS.js, 30, 18))
+
+object.spaace = 12 // error on write
+>object : Symbol(object, Decl(spellingUncheckedJS.js, 26, 3), Decl(spellingUncheckedJS.js, 29, 15), Decl(spellingUncheckedJS.js, 30, 18))
+
+object.fresh = 12 // OK
+>object : Symbol(object, Decl(spellingUncheckedJS.js, 26, 3), Decl(spellingUncheckedJS.js, 29, 15), Decl(spellingUncheckedJS.js, 30, 18))
+
+other.puuuce // OK, from another file
+>other : Symbol(other, Decl(other.js, 3, 3))
+
+new Date().getGMTDate() // OK, from another file
+>Date : Symbol(Date, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.scripthost.d.ts, --, --))
+
+// No suggestions for globals from other files
+const atoc = setIntegral(() => console.log('ok'), 500)
+>atoc : Symbol(atoc, Decl(spellingUncheckedJS.js, 36, 5))
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+
+AudioBuffin // etc
+Jimmy
+>Jimmy : Symbol(Jimmy, Decl(other.js, 0, 3))
+
+Jon
+
+=== tests/cases/conformance/salsa/other.js ===
+var Jimmy = 1
+>Jimmy : Symbol(Jimmy, Decl(other.js, 0, 3))
+
+var John = 2
+>John : Symbol(John, Decl(other.js, 1, 3))
+
+Jon // error, it's from the same file
+var other = {
+>other : Symbol(other, Decl(other.js, 3, 3))
+
+    puuce: 4
+>puuce : Symbol(puuce, Decl(other.js, 3, 13))
+}
+
diff --git a/tests/baselines/reference/spellingUncheckedJS.types b/tests/baselines/reference/spellingUncheckedJS.types
new file mode 100644
index 0000000000000..61723e8da16ea
--- /dev/null
+++ b/tests/baselines/reference/spellingUncheckedJS.types
@@ -0,0 +1,152 @@
+=== tests/cases/conformance/salsa/spellingUncheckedJS.js ===
+export var inModule = 1
+>inModule : number
+>1 : 1
+
+inmodule.toFixed()
+>inmodule.toFixed() : error
+>inmodule.toFixed : error
+>inmodule : any
+>toFixed : any
+
+function f() {
+>f : () => void
+
+    var locals = 2 + true
+>locals : any
+>2 + true : any
+>2 : 2
+>true : true
+
+    locale.toFixed()
+>locale.toFixed() : error
+>locale.toFixed : error
+>locale : any
+>toFixed : any
+
+    // @ts-expect-error
+    localf.toExponential()
+>localf.toExponential() : error
+>localf.toExponential : error
+>localf : any
+>toExponential : any
+
+    // @ts-expect-error
+    "this is fine"
+>"this is fine" : "this is fine"
+}
+class Classe {
+>Classe : Classe
+
+    non = 'oui'
+>non : string
+>'oui' : "oui"
+
+    methode() {
+>methode : () => any
+
+        // no error on 'this' references
+        return this.none
+>this.none : error
+>this : this
+>none : any
+    }
+}
+class Derivee extends Classe {
+>Derivee : Derivee
+>Classe : Classe
+
+    methode() {
+>methode : () => any
+
+        // no error on 'super' references
+        return super.none
+>super.none : error
+>super : Classe
+>none : any
+    }
+}
+
+
+var object = {
+>object : { spaaace: number; }
+>{    spaaace: 3} : { spaaace: number; }
+
+    spaaace: 3
+>spaaace : number
+>3 : 3
+}
+object.spaaaace // error on read
+>object.spaaaace : error
+>object : { spaaace: number; }
+>spaaaace : any
+
+object.spaace = 12 // error on write
+>object.spaace = 12 : 12
+>object.spaace : error
+>object : { spaaace: number; }
+>spaace : any
+>12 : 12
+
+object.fresh = 12 // OK
+>object.fresh = 12 : 12
+>object.fresh : error
+>object : { spaaace: number; }
+>fresh : any
+>12 : 12
+
+other.puuuce // OK, from another file
+>other.puuuce : any
+>other : { puuce: number; }
+>puuuce : any
+
+new Date().getGMTDate() // OK, from another file
+>new Date().getGMTDate() : error
+>new Date().getGMTDate : error
+>new Date() : Date
+>Date : DateConstructor
+>getGMTDate : any
+
+// No suggestions for globals from other files
+const atoc = setIntegral(() => console.log('ok'), 500)
+>atoc : error
+>setIntegral(() => console.log('ok'), 500) : error
+>setIntegral : error
+>() => console.log('ok') : () => void
+>console.log('ok') : void
+>console.log : (...data: any[]) => void
+>console : Console
+>log : (...data: any[]) => void
+>'ok' : "ok"
+>500 : 500
+
+AudioBuffin // etc
+>AudioBuffin : error
+
+Jimmy
+>Jimmy : number
+
+Jon
+>Jon : error
+
+=== tests/cases/conformance/salsa/other.js ===
+var Jimmy = 1
+>Jimmy : number
+>1 : 1
+
+var John = 2
+>John : number
+>2 : 2
+
+Jon // error, it's from the same file
+>Jon : error
+
+var other = {
+>other : { puuce: number; }
+>{    puuce: 4} : { puuce: number; }
+
+    puuce: 4
+>puuce : number
+>4 : 4
+}
+
diff --git a/tests/cases/conformance/salsa/spellingUncheckedJS.ts b/tests/cases/conformance/salsa/spellingUncheckedJS.ts
new file mode 100644
index 0000000000000..d5a1e8ac5602f
--- /dev/null
+++ b/tests/cases/conformance/salsa/spellingUncheckedJS.ts
@@ -0,0 +1,51 @@
+// @noEmit: true
+// @allowJs: true
+// @filename: spellingUncheckedJS.js
+export var inModule = 1
+inmodule.toFixed()
+
+function f() {
+    var locals = 2 + true
+    locale.toFixed()
+    // @ts-expect-error
+    localf.toExponential()
+    // @ts-expect-error
+    "this is fine"
+}
+class Classe {
+    non = 'oui'
+    methode() {
+        // no error on 'this' references
+        return this.none
+    }
+}
+class Derivee extends Classe {
+    methode() {
+        // no error on 'super' references
+        return super.none
+    }
+}
+
+
+var object = {
+    spaaace: 3
+}
+object.spaaaace // error on read
+object.spaace = 12 // error on write
+object.fresh = 12 // OK
+other.puuuce // OK, from another file
+new Date().getGMTDate() // OK, from another file
+
+// No suggestions for globals from other files
+const atoc = setIntegral(() => console.log('ok'), 500)
+AudioBuffin // etc
+Jimmy
+Jon
+
+// @filename: other.js
+var Jimmy = 1
+var John = 2
+Jon // error, it's from the same file
+var other = {
+    puuce: 4
+}
diff --git a/tests/cases/fourslash/codeFixSpellingJs1.ts b/tests/cases/fourslash/codeFixSpellingJs1.ts
new file mode 100644
index 0000000000000..4ad4d000d45f5
--- /dev/null
+++ b/tests/cases/fourslash/codeFixSpellingJs1.ts
@@ -0,0 +1,27 @@
+/// <reference path='fourslash.ts' />
+
+// @allowjs: true
+// @noEmit: true
+
+// @filename: a.js
+//// function f() {
+////     var locals = 2
+////     [|locale|].toFixed()
+////     return locals
+//// }
+
+verify.noErrors()
+verify.codeFixAvailable([
+    { description: "Change spelling to 'locals'" },
+]);
+
+verify.codeFix({
+    description: "Change spelling to 'locals'",
+    index: 0,
+    newFileContent:
+`function f() {
+    var locals = 2
+    locals.toFixed()
+    return locals
+}`,
+});
diff --git a/tests/cases/fourslash/codeFixSpellingJs2.ts b/tests/cases/fourslash/codeFixSpellingJs2.ts
new file mode 100644
index 0000000000000..110737ade86c4
--- /dev/null
+++ b/tests/cases/fourslash/codeFixSpellingJs2.ts
@@ -0,0 +1,16 @@
+/// <reference path='fourslash.ts' />
+
+// @allowjs: true
+// @noEmit: true
+
+// @filename: a.js
+//// export var inModule = 1
+//// [|inmodule|].toFixed()
+
+verify.codeFix({
+    description: "Change spelling to 'inModule'",
+    index: 0,
+    newFileContent:
+`export var inModule = 1
+inModule.toFixed()`,
+});
diff --git a/tests/cases/fourslash/codeFixSpellingJs3.ts b/tests/cases/fourslash/codeFixSpellingJs3.ts
new file mode 100644
index 0000000000000..6451ce662ae3c
--- /dev/null
+++ b/tests/cases/fourslash/codeFixSpellingJs3.ts
@@ -0,0 +1,21 @@
+/// <reference path='fourslash.ts' />
+
+// @allowjs: true
+// @noEmit: true
+
+// @filename: a.js
+//// class Classe {
+////     non = 'oui'
+////     methode() {
+////         // no error on 'this' references
+////         return this.none
+////     }
+//// }
+//// class Derivee extends Classe {
+////     methode() {
+////         // no error on 'super' references
+////         return super.none
+////     }
+//// }
+verify.noErrors()
+
diff --git a/tests/cases/fourslash/codeFixSpellingJs4.ts b/tests/cases/fourslash/codeFixSpellingJs4.ts
new file mode 100644
index 0000000000000..97c6af2dce166
--- /dev/null
+++ b/tests/cases/fourslash/codeFixSpellingJs4.ts
@@ -0,0 +1,23 @@
+/// <reference path='fourslash.ts' />
+
+// @allowjs: true
+// @noEmit: true
+
+// @filename: a.js
+//// var object = {
+////     spaaace: 3
+//// }
+//// object.spaaaace // error on read
+//// object.spaace = 12 // error on write
+//// object.fresh = 12 // OK
+verify.codeFixAll({
+    fixId: "fixSpelling",
+    fixAllDescription: "Fix all detected spelling errors",
+    newFileContent:
+`var object = {
+    spaaace: 3
+}
+object.spaaace // error on read
+object.spaaace = 12 // error on write
+object.fresh = 12 // OK`,
+});
diff --git a/tests/cases/fourslash/codeFixSpellingJs5.ts b/tests/cases/fourslash/codeFixSpellingJs5.ts
new file mode 100644
index 0000000000000..478cc9208e178
--- /dev/null
+++ b/tests/cases/fourslash/codeFixSpellingJs5.ts
@@ -0,0 +1,26 @@
+/// <reference path='fourslash.ts' />
+
+// @allowjs: true
+// @noEmit: true
+
+// @filename: a.js
+//// var other = {
+////     puuce: 4
+//// }
+//// var Jimmy = 1
+//// var John = 2
+
+// @filename: b.js
+//// other.puuuce // OK, from another file
+//// new Date().getGMTDate() // OK, from another file
+//// window.argle // OK, from globalThis
+//// self.blargle // OK, from globalThis
+////
+//// // No suggestions for globals from other files
+//// const atoc = setIntegral(() => console.log('ok'), 500)
+//// AudioBuffin // etc
+//// Jimmy
+//// Jon
+
+
+verify.noErrors()
diff --git a/tests/cases/fourslash/codeFixSpellingJs6.ts b/tests/cases/fourslash/codeFixSpellingJs6.ts
new file mode 100644
index 0000000000000..535a80d2d80c3
--- /dev/null
+++ b/tests/cases/fourslash/codeFixSpellingJs6.ts
@@ -0,0 +1,56 @@
+/// <reference path='fourslash.ts' />
+
+// @allowjs: true
+// @checkjs: false
+// @noEmit: true
+// @filename: spellingUncheckedJS.js
+//// export var inModule = 1
+//// inmodule.toFixed()
+////
+//// function f() {
+////     var locals = 2 + true
+////     locale.toFixed()
+//// }
+//// class Classe {
+////     non = 'oui'
+////     methode() {
+////         // no error on 'this' references
+////         return this.none
+////     }
+//// }
+//// class Derivee extends Classe {
+////     methode() {
+////         // no error on 'super' references
+////         return super.none
+////     }
+//// }
+////
+////
+//// var object = {
+////     spaaace: 3
+//// }
+//// object.spaaaace // error on read
+//// object.spaace = 12 // error on write
+//// object.fresh = 12 // OK
+//// other.puuuce // OK, from another file
+//// new Date().getGMTDate() // OK, from another file
+////
+//// // No suggestions for globals from other files
+//// const atoc = setIntegral(() => console.log('ok'), 500)
+//// AudioBuffin // etc
+//// Jimmy
+//// Jon
+//// window.argle
+//// self.blargle
+
+// @filename: other.js
+//// var Jimmy = 1
+//// var John = 2
+//// Jon // error, it's from the same file
+//// var other = {
+////     puuce: 4
+//// }
+//// window.argle
+//// self.blargle
+
+verify.noErrors()
diff --git a/tests/cases/fourslash/codeFixSpellingJs7.ts b/tests/cases/fourslash/codeFixSpellingJs7.ts
new file mode 100644
index 0000000000000..b5c6df2c9d08a
--- /dev/null
+++ b/tests/cases/fourslash/codeFixSpellingJs7.ts
@@ -0,0 +1,57 @@
+/// <reference path='fourslash.ts' />
+
+// @allowjs: true
+// @noEmit: true
+// @filename: spellingUncheckedJS.js
+//// // @ts-nocheck
+//// export var inModule = 1
+//// inmodule.toFixed()
+////
+//// function f() {
+////     var locals = 2 + true
+////     locale.toFixed()
+//// }
+//// class Classe {
+////     non = 'oui'
+////     methode() {
+////         // no error on 'this' references
+////         return this.none
+////     }
+//// }
+//// class Derivee extends Classe {
+////     methode() {
+////         // no error on 'super' references
+////         return super.none
+////     }
+//// }
+////
+////
+//// var object = {
+////     spaaace: 3
+//// }
+//// object.spaaaace // error on read
+//// object.spaace = 12 // error on write
+//// object.fresh = 12 // OK
+//// other.puuuce // OK, from another file
+//// new Date().getGMTDate() // OK, from another file
+////
+//// // No suggestions for globals from other files
+//// const atoc = setIntegral(() => console.log('ok'), 500)
+//// AudioBuffin // etc
+//// Jimmy
+//// Jon
+//// window.argle
+//// self.blargle
+
+// @filename: other.js
+//// // @ts-nocheck
+//// var Jimmy = 1
+//// var John = 2
+//// Jon // error, it's from the same file
+//// var other = {
+////     puuce: 4
+//// }
+//// window.argle
+//// self.blargle
+
+verify.noErrors()
diff --git a/tests/cases/fourslash/codeFixSpellingJs8.ts b/tests/cases/fourslash/codeFixSpellingJs8.ts
new file mode 100644
index 0000000000000..f43f9902592c0
--- /dev/null
+++ b/tests/cases/fourslash/codeFixSpellingJs8.ts
@@ -0,0 +1,10 @@
+/// <reference path='fourslash.ts' />
+
+// @allowjs: true
+// @noEmit: true
+
+// @filename: a.js
+//// var locals = {}
+//// // @ts-expect-error
+//// Object.keys(locale)
+verify.noErrors()
diff --git a/tests/cases/fourslash/codeFixUnusedIdentifier_delete_templateTag.ts b/tests/cases/fourslash/codeFixUnusedIdentifier_delete_templateTag.ts
index 5c0dae5b521dd..8d4466c777b29 100644
--- a/tests/cases/fourslash/codeFixUnusedIdentifier_delete_templateTag.ts
+++ b/tests/cases/fourslash/codeFixUnusedIdentifier_delete_templateTag.ts
@@ -53,6 +53,7 @@ function second(p) { return p; }`,
 goTo.file("/both.js");
 verify.codeFix({
     description: "Remove template tag",
+    index: 0,
     newFileContent:
 `/**
  * */
diff --git a/tests/cases/fourslash/codeFixUnusedIdentifier_jsdocTypeParameter.ts b/tests/cases/fourslash/codeFixUnusedIdentifier_jsdocTypeParameter.ts
index 9367a1214d8f0..4d6d624bd3f9a 100644
--- a/tests/cases/fourslash/codeFixUnusedIdentifier_jsdocTypeParameter.ts
+++ b/tests/cases/fourslash/codeFixUnusedIdentifier_jsdocTypeParameter.ts
@@ -10,6 +10,7 @@
 
 verify.codeFix({
     description: "Remove type parameters",
+    index: 0,
     newFileContent:
 `/**
  * @type {() => void}
diff --git a/tests/cases/fourslash/convertToEs6Class_emptyCatchClause.ts b/tests/cases/fourslash/convertToEs6Class_emptyCatchClause.ts
index fa6353397ca39..9c23d6c0378ed 100644
--- a/tests/cases/fourslash/convertToEs6Class_emptyCatchClause.ts
+++ b/tests/cases/fourslash/convertToEs6Class_emptyCatchClause.ts
@@ -9,6 +9,7 @@
 
 verify.codeFix({
     description: "Convert function to an ES2015 class",
+    index: 0,
     newFileContent:
 `class MyClass {
     constructor() { }