A method of automated candidate repair patch generation may include synthesizing repair expressions based on project code. Concise repair expressions may be mined from a code database. A set of repair expressions may be generated based on the synthesized repair expressions and the mined repair expressions. The set of repair expressions may include further repair expressions further synthesized from the synthesized repair expressions and the mined repair expressions. Candidate patches may be generated based on a repair schema and the set of repair expressions.