auto merge of #9013 : alexcrichton/rust/generated-unsafe-blocks, r=sanxiyn

This way syntax extensions can generate unsafe blocks without worrying about them generating unnecessary unsafe warnings. Perhaps a special keyword could be added to be used in macros, but I don't think that's the best solution.

Currently if you use `format!` and friends in an `unsafe` block you're guaranteed to get some unused-unsafe warnings which is unfortunate. We normally do want these warnings, but I'm ok ignoring them in the case of compiler-generated unsafe blocks. I tried to do this in the least intrusive way possible, but others may have better ideas about how to do this.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libsyntax/ext/ifmt.rs b/src/libsyntax/ext/ifmt.rs
index b7722ffc297..486069db4f0 100644
--- a/src/libsyntax/ext/ifmt.rs
+++ b/src/libsyntax/ext/ifmt.rs
@@ -632,7 +632,7 @@ impl Context {
            stmts: ~[],
            expr: Some(result),
            id: ast::DUMMY_NODE_ID,
-           rules: ast::UnsafeBlock,
+           rules: ast::UnsafeBlock(ast::CompilerGenerated),
            span: self.fmtsp,
         });