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Andy
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Error on rest parameter with trailing comma (#22262)
* Error on rest parameter with trailing comma * Error on binding patterns and improve error location
1 parent a0fe072 commit 9d713b6

13 files changed

+156
-22
lines changed

‎src/compiler/checker.ts‎

Lines changed: 7 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -19164,6 +19164,7 @@ namespace ts {
1916419164

1916519165
function checkObjectLiteralAssignment(node: ObjectLiteralExpression, sourceType: Type): Type {
1916619166
const properties = node.properties;
19167+
checkGrammarForDisallowedTrailingComma(properties, Diagnostics.A_rest_parameter_or_binding_pattern_may_not_have_a_trailing_comma);
1916719168
if (strictNullChecks && properties.length === 0) {
1916819169
return checkNonNullType(sourceType, node);
1916919170
}
@@ -19222,6 +19223,8 @@ namespace ts {
1922219223
}
1922319224

1922419225
function checkArrayLiteralAssignment(node: ArrayLiteralExpression, sourceType: Type, checkMode?: CheckMode): Type {
19226+
const elements = node.elements;
19227+
checkGrammarForDisallowedTrailingComma(elements, Diagnostics.A_rest_parameter_or_binding_pattern_may_not_have_a_trailing_comma);
1922519228
if (languageVersion < ScriptTarget.ES2015 && compilerOptions.downlevelIteration) {
1922619229
checkExternalEmitHelpers(node, ExternalEmitHelpers.Read);
1922719230
}
@@ -19230,7 +19233,6 @@ namespace ts {
1923019233
// present (aka the tuple element property). This call also checks that the parentType is in
1923119234
// fact an iterable or array (depending on target language).
1923219235
const elementType = checkIteratedTypeOrElementType(sourceType, node, /*allowStringInput*/ false, /*allowAsyncIterables*/ false) || unknownType;
19233-
const elements = node.elements;
1923419236
for (let i = 0; i < elements.length; i++) {
1923519237
checkArrayLiteralDestructuringElementAssignment(node, sourceType, i, elementType, checkMode);
1923619238
}
@@ -26500,11 +26502,9 @@ namespace ts {
2650026502
return grammarErrorOnNode(asyncModifier, Diagnostics._0_modifier_cannot_be_used_here, "async");
2650126503
}
2650226504

26503-
function checkGrammarForDisallowedTrailingComma(list: NodeArray<Node>): boolean {
26505+
function checkGrammarForDisallowedTrailingComma(list: NodeArray<Node>, diag = Diagnostics.Trailing_comma_not_allowed): boolean {
2650426506
if (list && list.hasTrailingComma) {
26505-
const start = list.end - ",".length;
26506-
const end = list.end;
26507-
return grammarErrorAtPos(list[0], start, end - start, Diagnostics.Trailing_comma_not_allowed);
26507+
return grammarErrorAtPos(list[0], list.end - ",".length, ",".length, diag);
2650826508
}
2650926509
}
2651026510

@@ -26526,6 +26526,7 @@ namespace ts {
2652626526
if (i !== (parameterCount - 1)) {
2652726527
return grammarErrorOnNode(parameter.dotDotDotToken, Diagnostics.A_rest_parameter_must_be_last_in_a_parameter_list);
2652826528
}
26529+
checkGrammarForDisallowedTrailingComma(parameters, Diagnostics.A_rest_parameter_or_binding_pattern_may_not_have_a_trailing_comma);
2652926530

2653026531
if (isBindingPattern(parameter.name)) {
2653126532
return grammarErrorOnNode(parameter.name, Diagnostics.A_rest_element_cannot_contain_a_binding_pattern);
@@ -27140,6 +27141,7 @@ namespace ts {
2714027141
if (node !== last(elements)) {
2714127142
return grammarErrorOnNode(node, Diagnostics.A_rest_element_must_be_last_in_a_destructuring_pattern);
2714227143
}
27144+
checkGrammarForDisallowedTrailingComma(elements, Diagnostics.A_rest_parameter_or_binding_pattern_may_not_have_a_trailing_comma);
2714327145

2714427146
if (node.name.kind === SyntaxKind.ArrayBindingPattern || node.name.kind === SyntaxKind.ObjectBindingPattern) {
2714527147
return grammarErrorOnNode(node.name, Diagnostics.A_rest_element_cannot_contain_a_binding_pattern);

‎src/compiler/diagnosticMessages.json‎

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -27,6 +27,10 @@
2727
"category": "Error",
2828
"code": 1012
2929
},
30+
"A rest parameter or binding pattern may not have a trailing comma.": {
31+
"category": "Error",
32+
"code": 1013
33+
},
3034
"A rest parameter must be last in a parameter list.": {
3135
"category": "Error",
3236
"code": 1014

‎tests/baselines/reference/trailingCommasInBindingPatterns.errors.txt‎

Lines changed: 21 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,21 @@
1+
tests/cases/conformance/es7/trailingCommasInBindingPatterns.ts(1,12): error TS1013: A rest parameter or binding pattern may not have a trailing comma.
2+
tests/cases/conformance/es7/trailingCommasInBindingPatterns.ts(2,12): error TS1013: A rest parameter or binding pattern may not have a trailing comma.
3+
tests/cases/conformance/es7/trailingCommasInBindingPatterns.ts(4,7): error TS1013: A rest parameter or binding pattern may not have a trailing comma.
4+
tests/cases/conformance/es7/trailingCommasInBindingPatterns.ts(5,7): error TS1013: A rest parameter or binding pattern may not have a trailing comma.
5+
6+
7+
==== tests/cases/conformance/es7/trailingCommasInBindingPatterns.ts (4 errors) ====
8+
const [...a,] = [];
9+
~
10+
!!! error TS1013: A rest parameter or binding pattern may not have a trailing comma.
11+
const {...b,} = {};
12+
~
13+
!!! error TS1013: A rest parameter or binding pattern may not have a trailing comma.
14+
let c, d;
15+
([...c,] = []);
16+
~
17+
!!! error TS1013: A rest parameter or binding pattern may not have a trailing comma.
18+
({...d,} = {});
19+
~
20+
!!! error TS1013: A rest parameter or binding pattern may not have a trailing comma.
21+

‎tests/baselines/reference/trailingCommasInBindingPatterns.js‎

Lines changed: 23 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,23 @@
1+
//// [trailingCommasInBindingPatterns.ts]
2+
const [...a,] = [];
3+
const {...b,} = {};
4+
let c, d;
5+
([...c,] = []);
6+
({...d,} = {});
7+
8+
9+
//// [trailingCommasInBindingPatterns.js]
10+
var __rest = (this && this.__rest) || function (s, e) {
11+
var t = {};
12+
for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)
13+
t[p] = s[p];
14+
if (s != null && typeof Object.getOwnPropertySymbols === "function")
15+
for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)
16+
t[p[i]] = s[p[i]];
17+
return t;
18+
};
19+
var a = [].slice(0);
20+
var b = __rest({}, []);
21+
var c, d;
22+
(c = [].slice(0));
23+
(d = __rest({}, []));

‎tests/baselines/reference/trailingCommasInBindingPatterns.symbols‎

Lines changed: 17 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
1+
=== tests/cases/conformance/es7/trailingCommasInBindingPatterns.ts ===
2+
const [...a,] = [];
3+
>a : Symbol(a, Decl(trailingCommasInBindingPatterns.ts, 0, 7))
4+
5+
const {...b,} = {};
6+
>b : Symbol(b, Decl(trailingCommasInBindingPatterns.ts, 1, 7))
7+
8+
let c, d;
9+
>c : Symbol(c, Decl(trailingCommasInBindingPatterns.ts, 2, 3))
10+
>d : Symbol(d, Decl(trailingCommasInBindingPatterns.ts, 2, 6))
11+
12+
([...c,] = []);
13+
>c : Symbol(c, Decl(trailingCommasInBindingPatterns.ts, 2, 3))
14+
15+
({...d,} = {});
16+
>d : Symbol(d, Decl(trailingCommasInBindingPatterns.ts, 2, 6))
17+

‎tests/baselines/reference/trailingCommasInBindingPatterns.types‎

Lines changed: 28 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,28 @@
1+
=== tests/cases/conformance/es7/trailingCommasInBindingPatterns.ts ===
2+
const [...a,] = [];
3+
>a : any[]
4+
>[] : undefined[]
5+
6+
const {...b,} = {};
7+
>b : {}
8+
>{} : {}
9+
10+
let c, d;
11+
>c : any
12+
>d : any
13+
14+
([...c,] = []);
15+
>([...c,] = []) : undefined[]
16+
>[...c,] = [] : undefined[]
17+
>[...c,] : undefined[]
18+
>...c : any
19+
>c : any
20+
>[] : undefined[]
21+
22+
({...d,} = {});
23+
>({...d,} = {}) : {}
24+
>{...d,} = {} : {}
25+
>{...d,} : any
26+
>d : any
27+
>{} : {}
28+

‎tests/baselines/reference/trailingCommasInFunctionParametersAndArguments.errors.txt‎

Lines changed: 34 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,34 @@
1+
tests/cases/conformance/es7/trailingCommasInFunctionParametersAndArguments.ts(5,20): error TS1013: A rest parameter or binding pattern may not have a trailing comma.
2+
3+
4+
==== tests/cases/conformance/es7/trailingCommasInFunctionParametersAndArguments.ts (1 errors) ====
5+
function f1(x,) {}
6+
7+
f1(1,);
8+
9+
function f2(...args,) {}
10+
~
11+
!!! error TS1013: A rest parameter or binding pattern may not have a trailing comma.
12+
13+
f2(...[],);
14+
15+
// Not confused by overloads
16+
declare function f3(x, ): number;
17+
declare function f3(x, y,): string;
18+
19+
<number>f3(1,);
20+
<string>f3(1, 2,);
21+
22+
// Works for constructors too
23+
class X {
24+
constructor(a,) { }
25+
// See trailingCommasInGetter.ts
26+
set x(value,) { }
27+
}
28+
interface Y {
29+
new(x,);
30+
(x,);
31+
}
32+
33+
new X(1,);
34+

‎tests/baselines/reference/unusedLocalsAndObjectSpread2.errors.txt‎

Lines changed: 5 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,14 +1,14 @@
11
tests/cases/compiler/unusedLocalsAndObjectSpread2.ts(5,3): error TS6133: 'rest' is declared but its value is never read.
22
tests/cases/compiler/unusedLocalsAndObjectSpread2.ts(8,1): error TS6133: 'foo' is declared but its value is never read.
3-
tests/cases/compiler/unusedLocalsAndObjectSpread2.ts(12,5): error TS6133: 'rest' is declared but its value is never read.
3+
tests/cases/compiler/unusedLocalsAndObjectSpread2.ts(12,9): error TS6133: 'rest' is declared but its value is never read.
44

55

66
==== tests/cases/compiler/unusedLocalsAndObjectSpread2.ts (3 errors) ====
77
declare let props: any;
88
const {
99
children, // here!
1010
active: _a, // here!
11-
...rest,
11+
...rest
1212
~~~~~~~
1313
!!! error TS6133: 'rest' is declared but its value is never read.
1414
} = props;
@@ -19,10 +19,10 @@ tests/cases/compiler/unusedLocalsAndObjectSpread2.ts(12,5): error TS6133: 'rest'
1919
const {
2020
children,
2121
active: _a,
22-
...rest,
23-
~~~~~~~
22+
...rest
23+
~~~~~~~
2424
!!! error TS6133: 'rest' is declared but its value is never read.
25-
} = props;
25+
} = props;
2626
}
2727

2828
export const asdf = 123;

‎tests/baselines/reference/unusedLocalsAndObjectSpread2.js‎

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -3,15 +3,15 @@ declare let props: any;
33
const {
44
children, // here!
55
active: _a, // here!
6-
...rest,
6+
...rest
77
} = props;
88

99
function foo() {
1010
const {
1111
children,
1212
active: _a,
13-
...rest,
14-
} = props;
13+
...rest
14+
} = props;
1515
}
1616

1717
export const asdf = 123;

‎tests/baselines/reference/unusedLocalsAndObjectSpread2.symbols‎

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@ const {
99
active: _a, // here!
1010
>_a : Symbol(_a, Decl(unusedLocalsAndObjectSpread2.ts, 2, 13))
1111

12-
...rest,
12+
...rest
1313
>rest : Symbol(rest, Decl(unusedLocalsAndObjectSpread2.ts, 3, 15))
1414

1515
} = props;
@@ -25,10 +25,10 @@ function foo() {
2525
active: _a,
2626
>_a : Symbol(_a, Decl(unusedLocalsAndObjectSpread2.ts, 9, 17))
2727

28-
...rest,
28+
...rest
2929
>rest : Symbol(rest, Decl(unusedLocalsAndObjectSpread2.ts, 10, 19))
3030

31-
} = props;
31+
} = props;
3232
>props : Symbol(props, Decl(unusedLocalsAndObjectSpread2.ts, 0, 11))
3333
}
3434

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