Merge pull request #543 from eefriedman/macro-crash

Fix crash speculatively parsing macro arguments as expressions.

src/expr.rs

@@ -422,7 +422,7 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Opt
             return Some(user_str);
         }
 
-        let mut visitor = FmtVisitor::from_codemap(context.codemap, context.config, None);
+        let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config, None);
         visitor.block_indent = context.block_indent;
 
         let prefix = match self.rules {
@@ -833,7 +833,9 @@ fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Opt
         let attr_str = if !attrs.is_empty() {
             // We only use this visitor for the attributes, should we use it for
             // more?
-            let mut attr_visitor = FmtVisitor::from_codemap(context.codemap, context.config, None);
+            let mut attr_visitor = FmtVisitor::from_codemap(context.parse_session,
+                                                            context.config,
+                                                            None);
             attr_visitor.block_indent = context.block_indent;
             attr_visitor.last_pos = attrs[0].span.lo;
             if attr_visitor.visit_attrs(attrs) {

src/lib.rs

@@ -26,7 +26,8 @@
 extern crate term;
 
 use syntax::ast;
-use syntax::codemap::{CodeMap, Span};
+use syntax::codemap::Span;
+use syntax::diagnostic::{EmitterWriter, Handler};
 use syntax::parse::{self, ParseSess};
 
 use std::ops::{Add, Sub};
@@ -288,11 +289,15 @@ fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
 }
 
 // Formatting which depends on the AST.
-fn fmt_ast(krate: &ast::Crate, codemap: &CodeMap, config: &Config, mode: WriteMode) -> FileMap {
+fn fmt_ast(krate: &ast::Crate,
+           parse_session: &ParseSess,
+           config: &Config,
+           mode: WriteMode)
+           -> FileMap {
     let mut file_map = FileMap::new();
-    for (path, module) in modules::list_files(krate, codemap) {
+    for (path, module) in modules::list_files(krate, parse_session.codemap()) {
         let path = path.to_str().unwrap();
-        let mut visitor = FmtVisitor::from_codemap(codemap, config, Some(mode));
+        let mut visitor = FmtVisitor::from_codemap(parse_session, config, Some(mode));
         visitor.format_separate_mod(module, path);
         file_map.insert(path.to_owned(), visitor.buffer);
     }
@@ -382,9 +387,14 @@ pub fn fmt_lines(file_map: &mut FileMap, config: &Config) -> FormatReport {
 }
 
 pub fn format(file: &Path, config: &Config, mode: WriteMode) -> FileMap {
-    let parse_session = ParseSess::new();
+    let mut parse_session = ParseSess::new();
     let krate = parse::parse_crate_from_file(file, Vec::new(), &parse_session);
-    let mut file_map = fmt_ast(&krate, parse_session.codemap(), config, mode);
+
+    // Suppress error output after parsing.
+    let emitter = Box::new(EmitterWriter::new(Box::new(Vec::new()), None));
+    parse_session.span_diagnostic.handler = Handler::with_emitter(false, emitter);
+
+    let mut file_map = fmt_ast(&krate, &parse_session, config, mode);
 
     // For some reason, the codemap does not include terminating
     // newlines so we must add one on for each file. This is sad.

src/macros.rs

@@ -21,7 +21,7 @@
 
 use syntax::ast;
 use syntax::parse::token::{Eof, Comma, Token};
-use syntax::parse::{ParseSess, tts_to_parser};
+use syntax::parse::tts_to_parser;
 use syntax::codemap::{mk_sp, BytePos};
 
 use Indent;
@@ -73,8 +73,7 @@ pub fn rewrite_macro(mac: &ast::Mac,
         };
     }
 
-    let parse_session = ParseSess::new();
-    let mut parser = tts_to_parser(&parse_session, mac.node.tts.clone(), Vec::new());
+    let mut parser = tts_to_parser(context.parse_session, mac.node.tts.clone(), Vec::new());
     let mut expr_vec = Vec::new();
 
     loop {

src/rewrite.rs

@@ -11,6 +11,7 @@
 // A generic trait to abstract the rewriting of an element (of the AST).
 
 use syntax::codemap::{CodeMap, Span};
+use syntax::parse::ParseSess;
 
 use Indent;
 use config::Config;
@@ -27,6 +28,7 @@ pub trait Rewrite {
 }
 
 pub struct RewriteContext<'a> {
+    pub parse_session: &'a ParseSess,
     pub codemap: &'a CodeMap,
     pub config: &'a Config,
     // Indentation due to nesting of blocks.
@@ -36,6 +38,7 @@ pub struct RewriteContext<'a> {
 impl<'a> RewriteContext<'a> {
     pub fn nested_context(&self) -> RewriteContext<'a> {
         RewriteContext {
+            parse_session: self.parse_session,
             codemap: self.codemap,
             config: self.config,
             block_indent: self.block_indent.block_indent(self.config),

src/visitor.rs

@@ -10,6 +10,7 @@
 
 use syntax::ast;
 use syntax::codemap::{self, CodeMap, Span, BytePos};
+use syntax::parse::ParseSess;
 use syntax::visit;
 
 use strings::string_buffer::StringBuffer;
@@ -23,6 +24,7 @@
 use items::rewrite_static;
 
 pub struct FmtVisitor<'a> {
+    pub parse_session: &'a ParseSess,
     pub codemap: &'a CodeMap,
     pub buffer: StringBuffer,
     pub last_pos: BytePos,
@@ -363,12 +365,13 @@ fn push_rewrite(&mut self, span: Span, rewrite: Option<String>) {
         }
     }
 
-    pub fn from_codemap(codemap: &'a CodeMap,
+    pub fn from_codemap(parse_session: &'a ParseSess,
                         config: &'a Config,
                         mode: Option<WriteMode>)
                         -> FmtVisitor<'a> {
         FmtVisitor {
-            codemap: codemap,
+            parse_session: parse_session,
+            codemap: parse_session.codemap(),
             buffer: StringBuffer::new(),
             last_pos: BytePos(0),
             block_indent: Indent {
@@ -461,13 +464,10 @@ fn format_import(&mut self, vis: ast::Visibility, vp: &ast::ViewPath, span: Span
         let vis = utils::format_visibility(vis);
         let mut offset = self.block_indent;
         offset.alignment += vis.len() + "use ".len();
-        let context = RewriteContext {
-            codemap: self.codemap,
-            config: self.config,
-            block_indent: self.block_indent,
-        };
         // 1 = ";"
-        match vp.rewrite(&context, self.config.max_width - offset.width() - 1, offset) {
+        match vp.rewrite(&self.get_context(),
+                         self.config.max_width - offset.width() - 1,
+                         offset) {
             Some(ref s) if s.is_empty() => {
                 // Format up to last newline
                 let prev_span = codemap::mk_sp(self.last_pos, span.lo);
@@ -493,6 +493,7 @@ fn format_import(&mut self, vis: ast::Visibility, vp: &ast::ViewPath, span: Span
 
     pub fn get_context(&self) -> RewriteContext {
         RewriteContext {
+            parse_session: self.parse_session,
             codemap: self.codemap,
             config: self.config,
             block_indent: self.block_indent,

tests/source/macros.rs

@@ -27,4 +27,6 @@ fn main() {
     hamkaas!{ () };
 
     macrowithbraces! {dont,    format, me}
+
+    x!(fn);
 }

tests/target/macros.rs

@@ -30,4 +30,6 @@ fn main() {
     hamkaas!{ () };
 
     macrowithbraces! {dont,    format, me}
+
+    x!(fn);
 }