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Increase span of unreachable code error (#25388) #25555

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49 changes: 44 additions & 5 deletions src/compiler/binder.ts
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Expand Up @@ -1211,7 +1211,7 @@ namespace ts {
bind(node.statement);
popActiveLabel();
if (!activeLabel.referenced && !options.allowUnusedLabels) {
errorOrSuggestionOnFirstToken(unusedLabelIsError(options), node, Diagnostics.Unused_label);
errorOrSuggestionOnNode(unusedLabelIsError(options), node.label, Diagnostics.Unused_label);
}
if (!node.statement || node.statement.kind !== SyntaxKind.DoStatement) {
// do statement sets current flow inside bindDoStatement
Expand Down Expand Up @@ -1918,9 +1918,16 @@ namespace ts {
file.bindDiagnostics.push(createFileDiagnostic(file, span.start, span.length, message, arg0, arg1, arg2));
}

function errorOrSuggestionOnFirstToken(isError: boolean, node: Node, message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any) {
const span = getSpanOfTokenAtPosition(file, node.pos);
const diag = createFileDiagnostic(file, span.start, span.length, message, arg0, arg1, arg2);
function errorOrSuggestionOnNode(isError: boolean, node: Node, message: DiagnosticMessage): void {
errorOrSuggestionOnRange(isError, node, node, message);
}

function errorOrSuggestionOnRange(isError: boolean, startNode: Node, endNode: Node, message: DiagnosticMessage): void {
addErrorOrSuggestionDiagnostic(isError, { pos: getTokenPosOfNode(startNode, file), end: endNode.end }, message);
}

function addErrorOrSuggestionDiagnostic(isError: boolean, range: TextRange, message: DiagnosticMessage): void {
const diag = createFileDiagnostic(file, range.pos, range.end - range.pos, message);
if (isError) {
file.bindDiagnostics.push(diag);
}
Expand Down Expand Up @@ -2792,14 +2799,46 @@ namespace ts {
node.declarationList.declarations.some(d => !!d.initializer)
);

errorOrSuggestionOnFirstToken(isError, node, Diagnostics.Unreachable_code_detected);
eachUnreachableRange(node, (start, end) => errorOrSuggestionOnRange(isError, start, end, Diagnostics.Unreachable_code_detected));
}
}
}
return true;
}
}

function eachUnreachableRange(node: Node, cb: (start: Node, last: Node) => void): void {
if (isStatement(node) && isExecutableStatement(node) && isBlock(node.parent)) {
const { statements } = node.parent;
const slice = sliceAfter(statements, node);
getRangesWhere(slice, isExecutableStatement, (start, afterEnd) => cb(slice[start], slice[afterEnd - 1]));
}
else {
cb(node, node);
}
}
// As opposed to a pure declaration like an `interface`
function isExecutableStatement(s: Statement): boolean {
// Don't remove statements that can validly be used before they appear.
return !isFunctionDeclaration(s) && !isPurelyTypeDeclaration(s) &&
// `var x;` may declare a variable used above
!(isVariableStatement(s) && !(getCombinedNodeFlags(s) & (NodeFlags.Let | NodeFlags.Const)) && s.declarationList.declarations.some(d => !d.initializer));
}

function isPurelyTypeDeclaration(s: Statement): boolean {
switch (s.kind) {
case SyntaxKind.InterfaceDeclaration:
case SyntaxKind.TypeAliasDeclaration:
return true;
case SyntaxKind.ModuleDeclaration:
return getModuleInstanceState(s as ModuleDeclaration) !== ModuleInstanceState.Instantiated;
case SyntaxKind.EnumDeclaration:
return hasModifier(s, ModifierFlags.Const);
default:
return false;
}
}

/* @internal */
export function isExportsOrModuleExportsOrAlias(sourceFile: SourceFile, node: Expression): boolean {
return isExportsIdentifier(node) ||
Expand Down
6 changes: 6 additions & 0 deletions src/compiler/utilities.ts
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Expand Up @@ -8108,4 +8108,10 @@ namespace ts {
}

export type Mutable<T extends object> = { -readonly [K in keyof T]: T[K] };

export function sliceAfter<T>(arr: ReadonlyArray<T>, value: T): ReadonlyArray<T> {
const index = arr.indexOf(value);
Debug.assert(index !== -1);
return arr.slice(index);
}
}
45 changes: 12 additions & 33 deletions src/services/codefixes/fixUnreachableCode.ts
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Expand Up @@ -5,14 +5,14 @@ namespace ts.codefix {
registerCodeFix({
errorCodes,
getCodeActions(context) {
const changes = textChanges.ChangeTracker.with(context, t => doChange(t, context.sourceFile, context.span.start));
const changes = textChanges.ChangeTracker.with(context, t => doChange(t, context.sourceFile, context.span.start, context.span.length));
return [createCodeFixAction(fixId, changes, Diagnostics.Remove_unreachable_code, fixId, Diagnostics.Remove_all_unreachable_code)];
},
fixIds: [fixId],
getAllCodeActions: context => codeFixAll(context, errorCodes, (changes, diag) => doChange(changes, diag.file, diag.start)),
getAllCodeActions: context => codeFixAll(context, errorCodes, (changes, diag) => doChange(changes, diag.file, diag.start, diag.length)),
});

function doChange(changes: textChanges.ChangeTracker, sourceFile: SourceFile, start: number): void {
function doChange(changes: textChanges.ChangeTracker, sourceFile: SourceFile, start: number, length: number): void {
const token = getTokenAtPosition(sourceFile, start);
const statement = findAncestor(token, isStatement)!;
Debug.assert(statement.getStart(sourceFile) === token.getStart(sourceFile));
Expand All @@ -36,43 +36,22 @@ namespace ts.codefix {
break;
default:
if (isBlock(statement.parent)) {
split(sliceAfter(statement.parent.statements, statement), shouldRemove, (start, end) => changes.deleteNodeRange(sourceFile, start, end));
const end = start + length;
const lastStatement = Debug.assertDefined(lastWhere(sliceAfter(statement.parent.statements, statement), s => s.pos < end));
changes.deleteNodeRange(sourceFile, statement, lastStatement);
}
else {
changes.delete(sourceFile, statement);
}
}
}

function shouldRemove(s: Statement): boolean {
// Don't remove statements that can validly be used before they appear.
return !isFunctionDeclaration(s) && !isPurelyTypeDeclaration(s) &&
// `var x;` may declare a variable used above
!(isVariableStatement(s) && !(getCombinedNodeFlags(s) & (NodeFlags.Let | NodeFlags.Const)) && s.declarationList.declarations.some(d => !d.initializer));
}

function isPurelyTypeDeclaration(s: Statement): boolean {
switch (s.kind) {
case SyntaxKind.InterfaceDeclaration:
case SyntaxKind.TypeAliasDeclaration:
return true;
case SyntaxKind.ModuleDeclaration:
return getModuleInstanceState(s as ModuleDeclaration) !== ModuleInstanceState.Instantiated;
case SyntaxKind.EnumDeclaration:
return hasModifier(s, ModifierFlags.Const);
default:
return false;
function lastWhere<T>(a: ReadonlyArray<T>, pred: (value: T) => boolean): T | undefined {
let last: T | undefined;
for (const value of a) {
if (!pred(value)) break;
last = value;
}
}

function sliceAfter<T>(arr: ReadonlyArray<T>, value: T): ReadonlyArray<T> {
const index = arr.indexOf(value);
Debug.assert(index !== -1);
return arr.slice(index);
}

// Calls 'cb' with the start and end of each range where 'pred' is true.
function split<T>(arr: ReadonlyArray<T>, pred: (t: T) => boolean, cb: (start: T, end: T) => void): void {
getRangesWhere(arr, pred, (start, afterEnd) => cb(arr[start], arr[afterEnd - 1]));
return last;
}
}
1 change: 1 addition & 0 deletions tests/baselines/reference/api/tsserverlibrary.d.ts
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Expand Up @@ -7399,6 +7399,7 @@ declare namespace ts {
type Mutable<T extends object> = {
-readonly [K in keyof T]: T[K];
};
function sliceAfter<T>(arr: ReadonlyArray<T>, value: T): ReadonlyArray<T>;
}
declare namespace ts {
function createNode(kind: SyntaxKind, pos?: number, end?: number): Node;
Expand Down
8 changes: 4 additions & 4 deletions tests/baselines/reference/cf.errors.txt
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Expand Up @@ -14,7 +14,7 @@ tests/cases/compiler/cf.ts(36,13): error TS7027: Unreachable code detected.
if (y==7) {
continue L1;
x=11;
~
~~~~~
!!! error TS7027: Unreachable code detected.
}
if (y==3) {
Expand All @@ -28,7 +28,7 @@ tests/cases/compiler/cf.ts(36,13): error TS7027: Unreachable code detected.
if (y==20) {
break;
x=12;
~
~~~~~
!!! error TS7027: Unreachable code detected.
}
} while (y<41);
Expand All @@ -41,13 +41,13 @@ tests/cases/compiler/cf.ts(36,13): error TS7027: Unreachable code detected.
L3: if (x<y) {
break L2;
x=13;
~
~~~~~
!!! error TS7027: Unreachable code detected.
}
else {
break L3;
x=14;
~
~~~~~
!!! error TS7027: Unreachable code detected.
}
}
Expand Down
2 changes: 1 addition & 1 deletion tests/baselines/reference/jsFileCompilationBindErrors.errors.txt
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Expand Up @@ -15,7 +15,7 @@ tests/cases/compiler/a.js(11,9): error TS1100: Invalid use of 'arguments' in str
function f() {
return;
return; // Error: Unreachable code detected.
~~~~~~
~~~~~~~
!!! error TS7027: Unreachable code detected.
}

Expand Down
2 changes: 1 addition & 1 deletion tests/baselines/reference/jsFileCompilationBindReachabilityErrors.errors.txt
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Expand Up @@ -22,7 +22,7 @@ tests/cases/compiler/a.js(19,1): error TS7028: Unused label.
function bar2() {
}
var x = 10; // error
~~~
~~~~~~~~~~~
!!! error TS7027: Unreachable code detected.
}

Expand Down
33 changes: 21 additions & 12 deletions tests/baselines/reference/reachabilityChecks1.errors.txt
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Expand Up @@ -10,13 +10,13 @@ tests/cases/compiler/reachabilityChecks1.ts(69,5): error TS7027: Unreachable cod
==== tests/cases/compiler/reachabilityChecks1.ts (7 errors) ====
while (true);
var x = 1;
~~~
~~~~~~~~~~
!!! error TS7027: Unreachable code detected.

module A {
while (true);
let x;
~~~
~~~~~~
!!! error TS7027: Unreachable code detected.
}

Expand All @@ -30,10 +30,12 @@ tests/cases/compiler/reachabilityChecks1.ts(69,5): error TS7027: Unreachable cod
module A2 {
while (true);
module A {
~~~~~~
!!! error TS7027: Unreachable code detected.
~~~~~~~~~~
var x = 1;
~~~~~~~~~~~~~~~~~~
}
~~~~~
!!! error TS7027: Unreachable code detected.
}

module A3 {
Expand All @@ -44,10 +46,12 @@ tests/cases/compiler/reachabilityChecks1.ts(69,5): error TS7027: Unreachable cod
module A4 {
while (true);
module A {
~~~~~~
!!! error TS7027: Unreachable code detected.
~~~~~~~~~~
const enum E { X }
~~~~~~~~~~~~~~~~~~~~~~~~~~
}
~~~~~
!!! error TS7027: Unreachable code detected.
}

function f1(x) {
Expand All @@ -63,9 +67,10 @@ tests/cases/compiler/reachabilityChecks1.ts(69,5): error TS7027: Unreachable cod
function f2() {
return;
class A {
~~~~~
!!! error TS7027: Unreachable code detected.
~~~~~~~~~
}
~~~~~
!!! error TS7027: Unreachable code detected.
}

module B {
Expand All @@ -78,21 +83,25 @@ tests/cases/compiler/reachabilityChecks1.ts(69,5): error TS7027: Unreachable cod
do {
} while (true);
enum E {
~~~~
!!! error TS7027: Unreachable code detected.
~~~~~~~~
X = 1
~~~~~~~~~~~~~
}
~~~~~
!!! error TS7027: Unreachable code detected.
}

function f4() {
if (true) {
throw new Error();
}
const enum E {
~~~~~
!!! error TS7027: Unreachable code detected.
~~~~~~~~~~~~~~
X = 1
~~~~~~~~~~~~~
}
~~~~~
!!! error TS7027: Unreachable code detected.
}


9 changes: 7 additions & 2 deletions tests/baselines/reference/reachabilityChecks2.errors.txt
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Expand Up @@ -6,12 +6,17 @@ tests/cases/compiler/reachabilityChecks2.ts(4,1): error TS7027: Unreachable code
const enum E { X }

module A4 {
~~~~~~
!!! error TS7027: Unreachable code detected.
~~~~~~~~~~~
while (true);
~~~~~~~~~~~~~~~~~
module A {
~~~~~~~~~~~~~~
const enum E { X }
~~~~~~~~~~~~~~~~~~~~~~~~~~
}
~~~~~
}
~
!!! error TS7027: Unreachable code detected.


6 changes: 3 additions & 3 deletions tests/baselines/reference/reachabilityChecks5.errors.txt
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Expand Up @@ -109,7 +109,7 @@ tests/cases/compiler/reachabilityChecks5.ts(122,13): error TS7027: Unreachable c
}
else {
return 1;
~~~~~~
~~~~~~~~~
!!! error TS7027: Unreachable code detected.
}
}
Expand All @@ -124,7 +124,7 @@ tests/cases/compiler/reachabilityChecks5.ts(122,13): error TS7027: Unreachable c
try {
while (false) {
return 1;
~~~~~~
~~~~~~~~~
!!! error TS7027: Unreachable code detected.
}
}
Expand Down Expand Up @@ -154,7 +154,7 @@ tests/cases/compiler/reachabilityChecks5.ts(122,13): error TS7027: Unreachable c
break test;
} while (true);
x++;
~
~~~~
!!! error TS7027: Unreachable code detected.
} while (true);
}
Expand Down
6 changes: 3 additions & 3 deletions tests/baselines/reference/reachabilityChecks6.errors.txt
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Expand Up @@ -106,7 +106,7 @@ tests/cases/compiler/reachabilityChecks6.ts(122,13): error TS7027: Unreachable c
}
else {
return 1;
~~~~~~
~~~~~~~~~
!!! error TS7027: Unreachable code detected.
}
}
Expand All @@ -121,7 +121,7 @@ tests/cases/compiler/reachabilityChecks6.ts(122,13): error TS7027: Unreachable c
try {
while (false) {
return 1;
~~~~~~
~~~~~~~~~
!!! error TS7027: Unreachable code detected.
}
}
Expand Down Expand Up @@ -151,7 +151,7 @@ tests/cases/compiler/reachabilityChecks6.ts(122,13): error TS7027: Unreachable c
break test;
} while (true);
x++;
~
~~~~
!!! error TS7027: Unreachable code detected.
} while (true);
}
Expand Down
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