Cherry-pick PR #46628 into release-4.5 (#46676)

Component commits:
9f9f3ed fix(46615): remove useless assertion. change error suggestion for rest params

Co-authored-by: Oleksandr T <oleksandr.tarasiuk@outlook.com>

src/compiler/checker.ts

@@ -21204,9 +21204,10 @@ namespace ts {
                         (isCallSignatureDeclaration(param.parent) || isMethodSignature(param.parent) || isFunctionTypeNode(param.parent)) &&
                         param.parent.parameters.indexOf(param) > -1 &&
                         (resolveName(param, param.name.escapedText, SymbolFlags.Type, undefined, param.name.escapedText, /*isUse*/ true) ||
-                         param.name.originalKeywordKind && isTypeNodeKind(param.name.originalKeywordKind))) {
+                        param.name.originalKeywordKind && isTypeNodeKind(param.name.originalKeywordKind))) {
                         const newName = "arg" + param.parent.parameters.indexOf(param);
-                        errorOrSuggestion(noImplicitAny, declaration, Diagnostics.Parameter_has_a_name_but_no_type_Did_you_mean_0_Colon_1, newName, declarationNameToString(param.name));
+                        const typeName = declarationNameToString(param.name) + (param.dotDotDotToken ? "[]" : "");
+                        errorOrSuggestion(noImplicitAny, declaration, Diagnostics.Parameter_has_a_name_but_no_type_Did_you_mean_0_Colon_1, newName, typeName);
                         return;
                     }
                     diagnostic = (declaration as ParameterDeclaration).dotDotDotToken ?

src/services/codefixes/addNameToNamelessParameter.ts

@@ -14,24 +14,24 @@ namespace ts.codefix {
 
     function makeChange(changeTracker: textChanges.ChangeTracker, sourceFile: SourceFile, pos: number) {
         const token = getTokenAtPosition(sourceFile, pos);
-        if (!isIdentifier(token)) {
-            return Debug.fail("add-name-to-nameless-parameter operates on identifiers, but got a " + Debug.formatSyntaxKind(token.kind));
-        }
         const param = token.parent;
         if (!isParameter(param)) {
             return Debug.fail("Tried to add a parameter name to a non-parameter: " + Debug.formatSyntaxKind(token.kind));
         }
+
         const i = param.parent.parameters.indexOf(param);
         Debug.assert(!param.type, "Tried to add a parameter name to a parameter that already had one.");
         Debug.assert(i > -1, "Parameter not found in parent parameter list.");
+
+        const typeNode = factory.createTypeReferenceNode(param.name as Identifier, /*typeArguments*/ undefined);
         const replacement = factory.createParameterDeclaration(
             /*decorators*/ undefined,
             param.modifiers,
             param.dotDotDotToken,
             "arg" + i,
             param.questionToken,
-            factory.createTypeReferenceNode(token, /*typeArguments*/ undefined),
+            param.dotDotDotToken ? factory.createArrayTypeNode(typeNode) : typeNode,
             param.initializer);
-        changeTracker.replaceNode(sourceFile, token, replacement);
+        changeTracker.replaceNode(sourceFile, param, replacement);
     }
 }

tests/baselines/reference/noImplicitAnyNamelessParameter.errors.txt

@@ -1,26 +1,30 @@
-tests/cases/compiler/noImplicitAnyNamelessParameter.ts(2,17): error TS7051: Parameter has a name but no type. Did you mean 'arg0: string'?
-tests/cases/compiler/noImplicitAnyNamelessParameter.ts(2,25): error TS7051: Parameter has a name but no type. Did you mean 'arg1: C'?
-tests/cases/compiler/noImplicitAnyNamelessParameter.ts(3,19): error TS7051: Parameter has a name but no type. Did you mean 'arg0: C'?
-tests/cases/compiler/noImplicitAnyNamelessParameter.ts(3,22): error TS7051: Parameter has a name but no type. Did you mean 'arg1: number'?
-tests/cases/compiler/noImplicitAnyNamelessParameter.ts(4,20): error TS7051: Parameter has a name but no type. Did you mean 'arg0: boolean'?
-tests/cases/compiler/noImplicitAnyNamelessParameter.ts(4,29): error TS7051: Parameter has a name but no type. Did you mean 'arg1: C'?
-tests/cases/compiler/noImplicitAnyNamelessParameter.ts(4,32): error TS7051: Parameter has a name but no type. Did you mean 'arg2: object'?
-tests/cases/compiler/noImplicitAnyNamelessParameter.ts(4,40): error TS7051: Parameter has a name but no type. Did you mean 'arg3: undefined'?
+tests/cases/compiler/noImplicitAnyNamelessParameter.ts(2,20): error TS7051: Parameter has a name but no type. Did you mean 'arg0: string[]'?
+tests/cases/compiler/noImplicitAnyNamelessParameter.ts(3,17): error TS7051: Parameter has a name but no type. Did you mean 'arg0: string'?
+tests/cases/compiler/noImplicitAnyNamelessParameter.ts(3,25): error TS7051: Parameter has a name but no type. Did you mean 'arg1: C'?
+tests/cases/compiler/noImplicitAnyNamelessParameter.ts(4,19): error TS7051: Parameter has a name but no type. Did you mean 'arg0: C'?
+tests/cases/compiler/noImplicitAnyNamelessParameter.ts(4,22): error TS7051: Parameter has a name but no type. Did you mean 'arg1: number'?
+tests/cases/compiler/noImplicitAnyNamelessParameter.ts(5,20): error TS7051: Parameter has a name but no type. Did you mean 'arg0: boolean'?
+tests/cases/compiler/noImplicitAnyNamelessParameter.ts(5,29): error TS7051: Parameter has a name but no type. Did you mean 'arg1: C'?
+tests/cases/compiler/noImplicitAnyNamelessParameter.ts(5,32): error TS7051: Parameter has a name but no type. Did you mean 'arg2: object'?
+tests/cases/compiler/noImplicitAnyNamelessParameter.ts(5,40): error TS7051: Parameter has a name but no type. Did you mean 'arg3: undefined'?
 
 
-==== tests/cases/compiler/noImplicitAnyNamelessParameter.ts (8 errors) ====
+==== tests/cases/compiler/noImplicitAnyNamelessParameter.ts (9 errors) ====
     class C { }
-    declare var x: (string, C) => void;
+    declare var a: { m(...string): void }
+                       ~~~~~~~~~
+!!! error TS7051: Parameter has a name but no type. Did you mean 'arg0: string[]'?
+    declare var b: (string, C) => void;
                     ~~~~~~
 !!! error TS7051: Parameter has a name but no type. Did you mean 'arg0: string'?
                             ~
 !!! error TS7051: Parameter has a name but no type. Did you mean 'arg1: C'?
-    declare var y: { (C, number): void };
+    declare var c: { (C, number): void };
                       ~
 !!! error TS7051: Parameter has a name but no type. Did you mean 'arg0: C'?
                          ~~~~~~
 !!! error TS7051: Parameter has a name but no type. Did you mean 'arg1: number'?
-    declare var z: { m(boolean, C, object, undefined): void }
+    declare var d: { m(boolean, C, object, undefined): void }
                        ~~~~~~~
 !!! error TS7051: Parameter has a name but no type. Did you mean 'arg0: boolean'?
                                 ~

tests/baselines/reference/noImplicitAnyNamelessParameter.js

@@ -1,8 +1,9 @@
 //// [noImplicitAnyNamelessParameter.ts]
 class C { }
-declare var x: (string, C) => void;
-declare var y: { (C, number): void };
-declare var z: { m(boolean, C, object, undefined): void }
+declare var a: { m(...string): void }
+declare var b: (string, C) => void;
+declare var c: { (C, number): void };
+declare var d: { m(boolean, C, object, undefined): void }
 // note: null and void do not parse correctly without a preceding parameter name
 
 

tests/baselines/reference/noImplicitAnyNamelessParameter.symbols

@@ -2,23 +2,28 @@
 class C { }
 >C : Symbol(C, Decl(noImplicitAnyNamelessParameter.ts, 0, 0))
 
-declare var x: (string, C) => void;
->x : Symbol(x, Decl(noImplicitAnyNamelessParameter.ts, 1, 11))
->string : Symbol(string, Decl(noImplicitAnyNamelessParameter.ts, 1, 16))
->C : Symbol(C, Decl(noImplicitAnyNamelessParameter.ts, 1, 23))
+declare var a: { m(...string): void }
+>a : Symbol(a, Decl(noImplicitAnyNamelessParameter.ts, 1, 11))
+>m : Symbol(m, Decl(noImplicitAnyNamelessParameter.ts, 1, 16))
+>string : Symbol(string, Decl(noImplicitAnyNamelessParameter.ts, 1, 19))
 
-declare var y: { (C, number): void };
->y : Symbol(y, Decl(noImplicitAnyNamelessParameter.ts, 2, 11))
->C : Symbol(C, Decl(noImplicitAnyNamelessParameter.ts, 2, 18))
->number : Symbol(number, Decl(noImplicitAnyNamelessParameter.ts, 2, 20))
+declare var b: (string, C) => void;
+>b : Symbol(b, Decl(noImplicitAnyNamelessParameter.ts, 2, 11))
+>string : Symbol(string, Decl(noImplicitAnyNamelessParameter.ts, 2, 16))
+>C : Symbol(C, Decl(noImplicitAnyNamelessParameter.ts, 2, 23))
 
-declare var z: { m(boolean, C, object, undefined): void }
->z : Symbol(z, Decl(noImplicitAnyNamelessParameter.ts, 3, 11))
->m : Symbol(m, Decl(noImplicitAnyNamelessParameter.ts, 3, 16))
->boolean : Symbol(boolean, Decl(noImplicitAnyNamelessParameter.ts, 3, 19))
->C : Symbol(C, Decl(noImplicitAnyNamelessParameter.ts, 3, 27))
->object : Symbol(object, Decl(noImplicitAnyNamelessParameter.ts, 3, 30))
->undefined : Symbol(undefined, Decl(noImplicitAnyNamelessParameter.ts, 3, 38))
+declare var c: { (C, number): void };
+>c : Symbol(c, Decl(noImplicitAnyNamelessParameter.ts, 3, 11))
+>C : Symbol(C, Decl(noImplicitAnyNamelessParameter.ts, 3, 18))
+>number : Symbol(number, Decl(noImplicitAnyNamelessParameter.ts, 3, 20))
+
+declare var d: { m(boolean, C, object, undefined): void }
+>d : Symbol(d, Decl(noImplicitAnyNamelessParameter.ts, 4, 11))
+>m : Symbol(m, Decl(noImplicitAnyNamelessParameter.ts, 4, 16))
+>boolean : Symbol(boolean, Decl(noImplicitAnyNamelessParameter.ts, 4, 19))
+>C : Symbol(C, Decl(noImplicitAnyNamelessParameter.ts, 4, 27))
+>object : Symbol(object, Decl(noImplicitAnyNamelessParameter.ts, 4, 30))
+>undefined : Symbol(undefined, Decl(noImplicitAnyNamelessParameter.ts, 4, 38))
 
 // note: null and void do not parse correctly without a preceding parameter name
 

tests/baselines/reference/noImplicitAnyNamelessParameter.types

@@ -2,18 +2,23 @@
 class C { }
 >C : C
 
-declare var x: (string, C) => void;
->x : (string: any, C: any) => void
+declare var a: { m(...string): void }
+>a : { m(...string: any[]): void; }
+>m : (...string: any[]) => void
+>string : any[]
+
+declare var b: (string, C) => void;
+>b : (string: any, C: any) => void
 >string : any
 >C : any
 
-declare var y: { (C, number): void };
->y : (C: any, number: any) => void
+declare var c: { (C, number): void };
+>c : (C: any, number: any) => void
 >C : any
 >number : any
 
-declare var z: { m(boolean, C, object, undefined): void }
->z : { m(boolean: any, C: any, object: any, undefined: any): void; }
+declare var d: { m(boolean, C, object, undefined): void }
+>d : { m(boolean: any, C: any, object: any, undefined: any): void; }
 >m : (boolean: any, C: any, object: any, undefined: any) => void
 >boolean : any
 >C : any

tests/cases/compiler/noImplicitAnyNamelessParameter.ts

@@ -1,6 +1,7 @@
 // @noImplicitAny: true
 class C { }
-declare var x: (string, C) => void;
-declare var y: { (C, number): void };
-declare var z: { m(boolean, C, object, undefined): void }
+declare var a: { m(...string): void }
+declare var b: (string, C) => void;
+declare var c: { (C, number): void };
+declare var d: { m(boolean, C, object, undefined): void }
 // note: null and void do not parse correctly without a preceding parameter name

tests/cases/fourslash/codeFixAddParameterNames2.ts

@@ -0,0 +1,6 @@
+/// <reference path='fourslash.ts' />
+
+// @noImplicitAny: true
+////type Rest = ([|...number|]) => void;
+
+verify.rangeAfterCodeFix("...arg0: number[]");

tests/cases/fourslash/codeFixAddParameterNames3.ts

@@ -0,0 +1,6 @@
+/// <reference path='fourslash.ts' />
+
+// @noImplicitAny: true
+////type Rest = ([|public string|]) => void;
+
+verify.rangeAfterCodeFix("public arg0: string");