src/vs/workbench/contrib/tasks/common/problemMatcher.ts/AbstractLineMatcher/fillProperty
class AbstractLineMatcher:	private fillProperty(data: IProblemData, property: keyof IProblemData, pattern: IProblemPattern, matches: RegExpExecArray, trim: boolean = false): void {
		const patternAtProperty = pattern[property];
		if (Types.isUndefined(data[property]) && !Types.isUndefined(patternAtProperty) && patternAtProperty < matches.length) {
			let value = matches[patternAtProperty];
			if (value !== undefined) {
				if (trim) {
					value = Strings.trim(value)!;
				}
				(data as any)[property] = value;
			}
		}
	}