Function checkInterfaceDeclaration

test/fixtures/snapshot/typescript.js:84621–84658

(node)

            return !(getFalsyFlags(flowType) & 32768 /* TypeFlags.Undefined */);
        }
        function checkInterfaceDeclaration(node) {
            // Grammar checking
            if (!checkGrammarDecoratorsAndModifiers(node))
                checkGrammarInterfaceDeclaration(node);
            checkTypeParameters(node.typeParameters);
            addLazyDiagnostic(function () {
                checkTypeNameIsReserved(node.name, ts.Diagnostics.Interface_name_cannot_be_0);
                checkExportsOnMergedDeclarations(node);
                var symbol = getSymbolOfNode(node);
                checkTypeParameterListsIdentical(symbol);
                // Only check this symbol once
                var firstInterfaceDecl = ts.getDeclarationOfKind(symbol, 258 /* SyntaxKind.InterfaceDeclaration */);
                if (node === firstInterfaceDecl) {
                    var type = getDeclaredTypeOfSymbol(symbol);
                    var typeWithThis = getTypeWithThisArgument(type);
                    // run subsequent checks only if first set succeeded
                    if (checkInheritedPropertiesAreIdentical(type, node.name)) {
                        for (var _i = 0, _a = getBaseTypes(type); _i < _a.length; _i++) {
                            var baseType = _a[_i];
                            checkTypeAssignableTo(typeWithThis, getTypeWithThisArgument(baseType, type.thisType), node.name, ts.Diagnostics.Interface_0_incorrectly_extends_interface_1);
                        }
                        checkIndexConstraints(type, symbol);
                    }
                }
                checkObjectTypeForDuplicateDeclarations(node);
            });
            ts.forEach(ts.getInterfaceBaseTypeNodes(node), function (heritageElement) {
                if (!ts.isEntityNameExpression(heritageElement.expression) || ts.isOptionalChain(heritageElement.expression)) {
                    error(heritageElement.expression, ts.Diagnostics.An_interface_can_only_extend_an_identifier_Slashqualified_name_with_optional_type_arguments);
                }
                checkTypeReferenceNode(heritageElement);
            });
            ts.forEach(node.members, checkSourceElement);
            addLazyDiagnostic(function () {
                checkTypeForDuplicateIndexSignatures(node);
                registerForUnusedIdentifiersCheck(node);
            });
        }
        function checkTypeAliasDeclaration(node) {
            // Grammar checking
            checkGrammarDecoratorsAndModifiers(node);