Method _parseTypeAnnotation

server/src/parser/parser.ts:2170–2205

(node: ExpressionNode)

    }

    private _parseTypeAnnotation(node: ExpressionNode): TypeAnnotationExpression {
        let rawExpression = node;
        let parsedExpression = node;

        if (rawExpression instanceof StringNode) {
            if (rawExpression.tokens.length > 1) {
                this._addError('Type hints cannot span multiple string literals', node);
            } else if (rawExpression.tokens[0].quoteTypeFlags & QuoteTypeFlags.Triplicate) {
                this._addError('Type hints cannot use triple quotes', node);
            } else if (rawExpression.tokens[0].quoteTypeFlags &
                    (QuoteTypeFlags.Raw | QuoteTypeFlags.Unicode | QuoteTypeFlags.Byte)) {
                this._addError('Type hints cannot use raw, unicode or byte string literals', node);
            } else if (rawExpression.tokens[0].value.length !== rawExpression.tokens[0].length - 2) {
                this._addError('Type hints cannot contain escape characters', node);
            } else {
                let stringValue = rawExpression.tokens[0].value;
                let tokenOffset = rawExpression.tokens[0].start;
                let parser = new Parser();
                let parseResults = parser.parseTextExpression(this._fileContents!,
                    tokenOffset + 1, stringValue.length, this._parseOptions);

                parseResults.diagnostics.forEach(diag => {
                    this._addError(diag.message, node);
                });

                if (parseResults.parseTree) {
                    parsedExpression = parseResults.parseTree;
                }
            }
        }

        return {
            rawExpression,
            expression: parsedExpression
        };
    }

    // Peeks at the next token and returns true if it can never
    // represent the start of an expression.