296 lines
13 KiB
JavaScript
296 lines
13 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.callExpressionAffectsControlFlow = exports.SignatureEffect = exports.getControlFlowEnd = exports.endsControlFlow = void 0;
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const ts = require("typescript");
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const node_1 = require("../typeguard/node");
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const util_1 = require("./util");
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function endsControlFlow(statement, checker) {
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return getControlFlowEnd(statement, checker).end;
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}
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exports.endsControlFlow = endsControlFlow;
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const defaultControlFlowEnd = { statements: [], end: false };
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function getControlFlowEnd(statement, checker) {
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return node_1.isBlockLike(statement) ? handleBlock(statement, checker) : getControlFlowEndWorker(statement, checker);
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}
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exports.getControlFlowEnd = getControlFlowEnd;
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function getControlFlowEndWorker(statement, checker) {
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switch (statement.kind) {
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case ts.SyntaxKind.ReturnStatement:
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case ts.SyntaxKind.ThrowStatement:
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case ts.SyntaxKind.ContinueStatement:
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case ts.SyntaxKind.BreakStatement:
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return { statements: [statement], end: true };
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case ts.SyntaxKind.Block:
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return handleBlock(statement, checker);
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case ts.SyntaxKind.ForStatement:
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case ts.SyntaxKind.WhileStatement:
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return handleForAndWhileStatement(statement, checker);
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case ts.SyntaxKind.ForOfStatement:
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case ts.SyntaxKind.ForInStatement:
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return handleForInOrOfStatement(statement, checker);
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case ts.SyntaxKind.DoStatement:
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return matchBreakOrContinue(getControlFlowEndWorker(statement.statement, checker), node_1.isBreakOrContinueStatement);
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case ts.SyntaxKind.IfStatement:
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return handleIfStatement(statement, checker);
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case ts.SyntaxKind.SwitchStatement:
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return matchBreakOrContinue(handleSwitchStatement(statement, checker), node_1.isBreakStatement);
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case ts.SyntaxKind.TryStatement:
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return handleTryStatement(statement, checker);
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case ts.SyntaxKind.LabeledStatement:
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return matchLabel(getControlFlowEndWorker(statement.statement, checker), statement.label);
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case ts.SyntaxKind.WithStatement:
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return getControlFlowEndWorker(statement.statement, checker);
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case ts.SyntaxKind.ExpressionStatement:
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if (checker === undefined)
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return defaultControlFlowEnd;
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return handleExpressionStatement(statement, checker);
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default:
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return defaultControlFlowEnd;
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}
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}
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function handleBlock(statement, checker) {
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const result = { statements: [], end: false };
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for (const s of statement.statements) {
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const current = getControlFlowEndWorker(s, checker);
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result.statements.push(...current.statements);
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if (current.end) {
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result.end = true;
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break;
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}
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}
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return result;
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}
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function handleForInOrOfStatement(statement, checker) {
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const end = matchBreakOrContinue(getControlFlowEndWorker(statement.statement, checker), node_1.isBreakOrContinueStatement);
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end.end = false; // loop body is guaranteed to be executed
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return end;
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}
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function handleForAndWhileStatement(statement, checker) {
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const constantCondition = statement.kind === ts.SyntaxKind.WhileStatement
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? getConstantCondition(statement.expression)
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: statement.condition === undefined || getConstantCondition(statement.condition);
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if (constantCondition === false)
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return defaultControlFlowEnd; // loop body is never executed
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const end = matchBreakOrContinue(getControlFlowEndWorker(statement.statement, checker), node_1.isBreakOrContinueStatement);
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if (constantCondition === undefined)
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end.end = false; // can't be sure that loop body is executed at all
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return end;
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}
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/** Simply detects `true` and `false` in conditions. That matches TypeScript's behavior. */
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function getConstantCondition(node) {
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switch (node.kind) {
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case ts.SyntaxKind.TrueKeyword:
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return true;
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case ts.SyntaxKind.FalseKeyword:
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return false;
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default:
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return;
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}
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}
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function handleIfStatement(node, checker) {
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switch (getConstantCondition(node.expression)) {
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case true:
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// else branch is never executed
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return getControlFlowEndWorker(node.thenStatement, checker);
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case false:
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// then branch is never executed
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return node.elseStatement === undefined
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? defaultControlFlowEnd
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: getControlFlowEndWorker(node.elseStatement, checker);
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}
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const then = getControlFlowEndWorker(node.thenStatement, checker);
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if (node.elseStatement === undefined)
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return {
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statements: then.statements,
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end: false,
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};
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const elze = getControlFlowEndWorker(node.elseStatement, checker);
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return {
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statements: [...then.statements, ...elze.statements],
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end: then.end && elze.end,
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};
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}
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function handleSwitchStatement(node, checker) {
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let hasDefault = false;
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const result = {
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statements: [],
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end: false,
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};
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for (const clause of node.caseBlock.clauses) {
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if (clause.kind === ts.SyntaxKind.DefaultClause)
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hasDefault = true;
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const current = handleBlock(clause, checker);
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result.end = current.end;
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result.statements.push(...current.statements);
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}
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result.end && (result.end = hasDefault || checker !== undefined && util_1.hasExhaustiveCaseClauses(node, checker));
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return result;
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}
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function handleTryStatement(node, checker) {
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let finallyResult;
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if (node.finallyBlock !== undefined) {
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finallyResult = handleBlock(node.finallyBlock, checker);
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// if 'finally' always ends control flow, we are not interested in any jump statements from 'try' or 'catch'
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if (finallyResult.end)
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return finallyResult;
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}
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const tryResult = handleBlock(node.tryBlock, checker);
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if (node.catchClause === undefined)
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return { statements: finallyResult.statements.concat(tryResult.statements), end: tryResult.end };
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const catchResult = handleBlock(node.catchClause.block, checker);
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return {
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statements: tryResult.statements
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// remove all throw statements and throwing function calls from the list of control flow statements inside tryBlock
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.filter((s) => s.kind !== ts.SyntaxKind.ThrowStatement && s.kind !== ts.SyntaxKind.ExpressionStatement)
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.concat(catchResult.statements, finallyResult === undefined ? [] : finallyResult.statements),
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end: tryResult.end && catchResult.end, // only ends control flow if try AND catch definitely end control flow
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};
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}
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/** Dotted name as TypeScript requires it for assertion signatures to affect control flow. */
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function isDottedNameWithExplicitTypeAnnotation(node, checker) {
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while (true) {
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switch (node.kind) {
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case ts.SyntaxKind.Identifier: {
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const symbol = checker.getExportSymbolOfSymbol(checker.getSymbolAtLocation(node));
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return isExplicitlyTypedSymbol(util_1.isSymbolFlagSet(symbol, ts.SymbolFlags.Alias) ? checker.getAliasedSymbol(symbol) : symbol, checker);
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}
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case ts.SyntaxKind.ThisKeyword:
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return isExplicitlyTypedThis(node);
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case ts.SyntaxKind.SuperKeyword:
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return true;
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case ts.SyntaxKind.PropertyAccessExpression:
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if (!isExplicitlyTypedSymbol(checker.getSymbolAtLocation(node), checker))
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return false;
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// falls through
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case ts.SyntaxKind.ParenthesizedExpression:
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node = node.expression;
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continue;
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default:
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return false;
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}
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}
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}
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function isExplicitlyTypedSymbol(symbol, checker) {
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if (symbol === undefined)
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return false;
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if (util_1.isSymbolFlagSet(symbol, ts.SymbolFlags.Function | ts.SymbolFlags.Method | ts.SymbolFlags.Class | ts.SymbolFlags.ValueModule))
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return true;
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if (!util_1.isSymbolFlagSet(symbol, ts.SymbolFlags.Variable | ts.SymbolFlags.Property))
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return false;
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if (symbol.valueDeclaration === undefined)
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return false;
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if (declarationHasExplicitTypeAnnotation(symbol.valueDeclaration))
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return true;
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return node_1.isVariableDeclaration(symbol.valueDeclaration) &&
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symbol.valueDeclaration.parent.parent.kind === ts.SyntaxKind.ForOfStatement &&
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isDottedNameWithExplicitTypeAnnotation(symbol.valueDeclaration.parent.parent.expression, checker);
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}
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function declarationHasExplicitTypeAnnotation(node) {
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if (ts.isJSDocPropertyLikeTag(node))
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return node.typeExpression !== undefined;
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return (node_1.isVariableDeclaration(node) ||
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node_1.isParameterDeclaration(node) ||
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node_1.isPropertyDeclaration(node) ||
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node_1.isPropertySignature(node)) && (util_1.isNodeFlagSet(node, ts.NodeFlags.JavaScriptFile)
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? ts.getJSDocType(node)
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: node.type) !== undefined;
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}
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function isExplicitlyTypedThis(node) {
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var _a;
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do {
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node = node.parent;
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if (node_1.isDecorator(node)) {
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// `this` in decorators always resolves outside of the containing class
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if (node.parent.kind === ts.SyntaxKind.Parameter && node_1.isClassLikeDeclaration(node.parent.parent.parent)) {
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node = node.parent.parent.parent.parent;
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}
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else if (node_1.isClassLikeDeclaration(node.parent.parent)) {
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node = node.parent.parent.parent;
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}
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else if (node_1.isClassLikeDeclaration(node.parent)) {
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node = node.parent.parent;
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}
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}
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} while (util_1.isFunctionScopeBoundary(node) !== 1 /* Function */ || node.kind === ts.SyntaxKind.ArrowFunction);
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return util_1.isFunctionWithBody(node) &&
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(util_1.isNodeFlagSet(node, ts.NodeFlags.JavaScriptFile)
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? ((_a = ts.getJSDocThisTag(node)) === null || _a === void 0 ? void 0 : _a.typeExpression) !== undefined
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: node.parameters.length !== 0 && util_1.isThisParameter(node.parameters[0]) && node.parameters[0].type !== undefined) ||
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node_1.isClassLikeDeclaration(node.parent);
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}
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var SignatureEffect;
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(function (SignatureEffect) {
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SignatureEffect[SignatureEffect["Never"] = 1] = "Never";
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SignatureEffect[SignatureEffect["Asserts"] = 2] = "Asserts";
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})(SignatureEffect = exports.SignatureEffect || (exports.SignatureEffect = {}));
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/**
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* Dermines whether a top level CallExpression has a control flow effect according to TypeScript's rules.
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* This handles functions returning `never` and `asserts`.
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*/
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function callExpressionAffectsControlFlow(node, checker) {
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var _a, _b, _c;
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if (!node_1.isExpressionStatement(node.parent) ||
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ts.isOptionalChain(node) ||
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!isDottedNameWithExplicitTypeAnnotation(node.expression, checker))
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return;
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const signature = checker.getResolvedSignature(node);
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if ((signature === null || signature === void 0 ? void 0 : signature.declaration) === undefined)
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return;
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const typeNode = ts.isJSDocSignature(signature.declaration)
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? (_b = (_a = signature.declaration.type) === null || _a === void 0 ? void 0 : _a.typeExpression) === null || _b === void 0 ? void 0 : _b.type
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: (_c = signature.declaration.type) !== null && _c !== void 0 ? _c : (util_1.isNodeFlagSet(signature.declaration, ts.NodeFlags.JavaScriptFile)
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? ts.getJSDocReturnType(signature.declaration)
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: undefined);
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if (typeNode === undefined)
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return;
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if (node_1.isTypePredicateNode(typeNode) && typeNode.assertsModifier !== undefined)
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return 2 /* Asserts */;
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return util_1.isTypeFlagSet(checker.getTypeFromTypeNode(typeNode), ts.TypeFlags.Never) ? 1 /* Never */ : undefined;
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}
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exports.callExpressionAffectsControlFlow = callExpressionAffectsControlFlow;
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function handleExpressionStatement(node, checker) {
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if (!node_1.isCallExpression(node.expression))
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return defaultControlFlowEnd;
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switch (callExpressionAffectsControlFlow(node.expression, checker)) {
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case 2 /* Asserts */:
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return { statements: [node], end: false };
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case 1 /* Never */:
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return { statements: [node], end: true };
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case undefined:
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return defaultControlFlowEnd;
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}
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}
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function matchBreakOrContinue(current, pred) {
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const result = {
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statements: [],
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end: current.end,
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};
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for (const statement of current.statements) {
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if (pred(statement) && statement.label === undefined) {
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result.end = false;
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continue;
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}
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result.statements.push(statement);
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}
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return result;
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}
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function matchLabel(current, label) {
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const result = {
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statements: [],
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end: current.end,
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};
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const labelText = label.text;
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for (const statement of current.statements) {
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switch (statement.kind) {
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case ts.SyntaxKind.BreakStatement:
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case ts.SyntaxKind.ContinueStatement:
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if (statement.label !== undefined && statement.label.text === labelText) {
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result.end = false;
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continue;
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}
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}
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result.statements.push(statement);
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}
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return result;
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}
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//# sourceMappingURL=control-flow.js.map
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