rust-lang/rust — pull request #19892 by pnkfelix (2014-12-15 21:45:25+00:00)
Title: graphviz drawing of constraints for region inference

Added -Z print-region-graph debugging option; produces graphviz visualization of region inference constraint graph.

Optionally uses environment variables RUST_REGION_GRAPH= and RUST_REGION_GRAPH_NODE= to select which file to output to and which AST node to print.