Print to stderr when a graphviz file can't be written

ecstatic-morse · ecstatic-morse · commit 3b873987381c · 2020-10-05T10:14:40.000-07:00
`warn` prints nothing by default
diff --git a/compiler/rustc_mir/src/dataflow/framework/engine.rs b/compiler/rustc_mir/src/dataflow/framework/engine.rs
@@ -248,7 +248,7 @@ where
 
         let res = write_graphviz_results(tcx, &body, &results, pass_name);
         if let Err(e) = res {
-            warn!("Failed to write graphviz dataflow results: {}", e);
+            error!("Failed to write graphviz dataflow results: {}", e);
         }
 
         results

Original file line number	Diff line number	Diff line change
`@@ -248,7 +248,7 @@ where`
`248`	`248`
`249`	`249`	`let res = write_graphviz_results(tcx, &body, &results, pass_name);`
`250`	`250`	`if let Err(e) = res {`
`251`		`- warn!("Failed to write graphviz dataflow results: {}", e);`
	`251`	`+ error!("Failed to write graphviz dataflow results: {}", e);`
`252`	`252`	`}`
`253`	`253`
`254`	`254`	`results`