rustdoc: add an --edition flag to compile docs/doctests with a certain edition

src/doc/rustdoc/src/unstable-features.md

@@ -348,6 +348,19 @@ details.
 
 [issue-display-warnings]: https://github.com/rust-lang/rust/issues/41574
 
+### `--edition`: control the edition of docs and doctests
+
+Using this flag looks like this:
+
+```bash
+$ rustdoc src/lib.rs -Z unstable-options --edition 2018
+$ rustdoc --test src/lib.rs -Z unstable-options --edition 2018
+```
+
+This flag allows rustdoc to treat your rust code as the given edition. It will compile doctests with
+the given edition as well. As with `rustc`, the default edition that `rustdoc` will use is `2015`
+(the first edition).
+
 ### `-Z force-unstable-if-unmarked`
 
 Using this flag looks like this:

src/librustdoc/core.rs

@@ -25,6 +25,7 @@ use rustc_metadata::cstore::CStore;
 
 use syntax::ast::NodeId;
 use syntax::codemap;
+use syntax::edition::Edition;
 use syntax::feature_gate::UnstableFeatures;
 use errors;
 use errors::emitter::ColorConfig;
@@ -120,7 +121,8 @@ pub fn run_core(search_paths: SearchPaths,
                 maybe_sysroot: Option<PathBuf>,
                 allow_warnings: bool,
                 crate_name: Option<String>,
-                force_unstable_if_unmarked: bool) -> (clean::Crate, RenderInfo)
+                force_unstable_if_unmarked: bool,
+                edition: Edition) -> (clean::Crate, RenderInfo)
 {
     // Parse, resolve, and typecheck the given crate.
 
@@ -144,6 +146,7 @@ pub fn run_core(search_paths: SearchPaths,
         actually_rustdoc: true,
         debugging_opts: config::DebuggingOptions {
             force_unstable_if_unmarked,
+            edition,
             ..config::basic_debugging_options()
         },
         ..config::basic_options().clone()

src/librustdoc/lib.rs

@@ -61,6 +61,7 @@ use std::path::{Path, PathBuf};
 use std::process;
 use std::sync::mpsc::channel;
 
+use syntax::edition::Edition;
 use externalfiles::ExternalHtml;
 use rustc::session::search_paths::SearchPaths;
 use rustc::session::config::{ErrorOutputType, RustcOptGroup, nightly_options, Externs};
@@ -270,6 +271,11 @@ pub fn opts() -> Vec<RustcOptGroup> {
                       \"main-suffix.css\"",
                      "PATH")
         }),
+        unstable("edition", |o| {
+            o.optopt("", "edition",
+                     "edition to use when compiling rust code (default: 2015)",
+                     "EDITION")
+        }),
     ]
 }
 
@@ -428,14 +434,23 @@ pub fn main_args(args: &[String]) -> isize {
     let sort_modules_alphabetically = !matches.opt_present("sort-modules-by-appearance");
     let resource_suffix = matches.opt_str("resource-suffix");
 
+    let edition = matches.opt_str("edition").unwrap_or("2015".to_string());
+    let edition = match edition.parse() {
+        Ok(e) => e,
+        Err(_) => {
+            print_error("could not parse edition");
+            return 1;
+        }
+    };
+
     match (should_test, markdown_input) {
         (true, true) => {
             return markdown::test(input, cfgs, libs, externs, test_args, maybe_sysroot,
-                                  display_warnings, linker)
+                                  display_warnings, linker, edition)
         }
         (true, false) => {
             return test::run(Path::new(input), cfgs, libs, externs, test_args, crate_name,
-                             maybe_sysroot, display_warnings, linker)
+                             maybe_sysroot, display_warnings, linker, edition)
         }
         (false, true) => return markdown::render(Path::new(input),
                                                  output.unwrap_or(PathBuf::from("doc")),
@@ -445,7 +460,7 @@ pub fn main_args(args: &[String]) -> isize {
     }
 
     let output_format = matches.opt_str("w");
-    let res = acquire_input(PathBuf::from(input), externs, &matches, move |out| {
+    let res = acquire_input(PathBuf::from(input), externs, edition, &matches, move |out| {
         let Output { krate, passes, renderinfo } = out;
         info!("going to format");
         match output_format.as_ref().map(|s| &**s) {
@@ -486,14 +501,15 @@ fn print_error<T>(error_message: T) where T: Display {
 /// and files and then generates the necessary rustdoc output for formatting.
 fn acquire_input<R, F>(input: PathBuf,
                        externs: Externs,
+                       edition: Edition,
                        matches: &getopts::Matches,
                        f: F)
                        -> Result<R, String>
 where R: 'static + Send, F: 'static + Send + FnOnce(Output) -> R {
     match matches.opt_str("r").as_ref().map(|s| &**s) {
-        Some("rust") => Ok(rust_input(input, externs, matches, f)),
+        Some("rust") => Ok(rust_input(input, externs, edition, matches, f)),
         Some(s) => Err(format!("unknown input format: {}", s)),
-        None => Ok(rust_input(input, externs, matches, f))
+        None => Ok(rust_input(input, externs, edition, matches, f))
     }
 }
 
@@ -519,8 +535,14 @@ fn parse_externs(matches: &getopts::Matches) -> Result<Externs, String> {
 /// generated from the cleaned AST of the crate.
 ///
 /// This form of input will run all of the plug/cleaning passes
-fn rust_input<R, F>(cratefile: PathBuf, externs: Externs, matches: &getopts::Matches, f: F) -> R
-where R: 'static + Send, F: 'static + Send + FnOnce(Output) -> R {
+fn rust_input<R, F>(cratefile: PathBuf,
+                    externs: Externs,
+                    edition: Edition,
+                    matches: &getopts::Matches,
+                    f: F) -> R
+where R: 'static + Send,
+      F: 'static + Send + FnOnce(Output) -> R
+{
     let mut default_passes = !matches.opt_present("no-defaults");
     let mut passes = matches.opt_strs("passes");
     let mut plugins = matches.opt_strs("plugins");
@@ -563,7 +585,7 @@ where R: 'static + Send, F: 'static + Send + FnOnce(Output) -> R {
         let (mut krate, renderinfo) =
             core::run_core(paths, cfgs, externs, Input::File(cratefile), triple, maybe_sysroot,
                            display_warnings, crate_name.clone(),
-                           force_unstable_if_unmarked);
+                           force_unstable_if_unmarked, edition);
 
         info!("finished with rustc");
 

src/librustdoc/markdown.rs

@@ -18,6 +18,7 @@ use testing;
 use rustc::session::search_paths::SearchPaths;
 use rustc::session::config::Externs;
 use syntax::codemap::DUMMY_SP;
+use syntax::edition::Edition;
 
 use externalfiles::{ExternalHtml, LoadStringError, load_string};
 
@@ -139,7 +140,7 @@ pub fn render(input: &Path, mut output: PathBuf, matches: &getopts::Matches,
 /// Run any tests/code examples in the markdown file `input`.
 pub fn test(input: &str, cfgs: Vec<String>, libs: SearchPaths, externs: Externs,
             mut test_args: Vec<String>, maybe_sysroot: Option<PathBuf>,
-            display_warnings: bool, linker: Option<PathBuf>) -> isize {
+            display_warnings: bool, linker: Option<PathBuf>, edition: Edition) -> isize {
     let input_str = match load_string(input) {
         Ok(s) => s,
         Err(LoadStringError::ReadFail) => return 1,
@@ -151,7 +152,7 @@ pub fn test(input: &str, cfgs: Vec<String>, libs: SearchPaths, externs: Externs,
     let mut collector = Collector::new(input.to_owned(), cfgs, libs, externs,
                                        true, opts, maybe_sysroot, None,
                                        Some(PathBuf::from(input)),
-                                       linker);
+                                       linker, edition);
     find_testable_code(&input_str, &mut collector, DUMMY_SP, None);
     test_args.insert(0, "rustdoctest".to_string());
     testing::test_main(&test_args, collector.tests,

src/librustdoc/test.rs

@@ -34,6 +34,7 @@ use rustc_metadata::cstore::CStore;
 use rustc_resolve::MakeGlobMap;
 use syntax::ast;
 use syntax::codemap::CodeMap;
+use syntax::edition::Edition;
 use syntax::feature_gate::UnstableFeatures;
 use syntax::with_globals;
 use syntax_pos::{BytePos, DUMMY_SP, Pos, Span, FileName};
@@ -57,7 +58,8 @@ pub fn run(input_path: &Path,
            crate_name: Option<String>,
            maybe_sysroot: Option<PathBuf>,
            display_warnings: bool,
-           linker: Option<PathBuf>)
+           linker: Option<PathBuf>,
+           edition: Edition)
            -> isize {
     let input = config::Input::File(input_path.to_owned());
 
@@ -70,6 +72,10 @@ pub fn run(input_path: &Path,
         unstable_features: UnstableFeatures::from_environment(),
         lint_cap: Some(::rustc::lint::Level::Allow),
         actually_rustdoc: true,
+        debugging_opts: config::DebuggingOptions {
+            edition,
+            ..config::basic_debugging_options()
+        },
         ..config::basic_options().clone()
     };
 
@@ -117,7 +123,8 @@ pub fn run(input_path: &Path,
                                        maybe_sysroot,
                                        Some(codemap),
                                        None,
-                                       linker);
+                                       linker,
+                                       edition);
 
     {
         let map = hir::map::map_crate(&sess, &cstore, &mut hir_forest, &defs);
@@ -177,8 +184,7 @@ fn run_test(test: &str, cratename: &str, filename: &FileName, line: usize,
             externs: Externs,
             should_panic: bool, no_run: bool, as_test_harness: bool,
             compile_fail: bool, mut error_codes: Vec<String>, opts: &TestOptions,
-            maybe_sysroot: Option<PathBuf>,
-            linker: Option<PathBuf>) {
+            maybe_sysroot: Option<PathBuf>, linker: Option<PathBuf>, edition: Edition) {
     // the test harness wants its own `main` & top level functions, so
     // never wrap the test in `fn main() { ... }`
     let (test, line_offset) = make_test(test, Some(cratename), as_test_harness, opts);
@@ -204,6 +210,10 @@ fn run_test(test: &str, cratename: &str, filename: &FileName, line: usize,
         },
         test: as_test_harness,
         unstable_features: UnstableFeatures::from_environment(),
+        debugging_opts: config::DebuggingOptions {
+            edition,
+            ..config::basic_debugging_options()
+        },
         ..config::basic_options().clone()
     };
 
@@ -467,13 +477,14 @@ pub struct Collector {
     codemap: Option<Lrc<CodeMap>>,
     filename: Option<PathBuf>,
     linker: Option<PathBuf>,
+    edition: Edition,
 }
 
 impl Collector {
     pub fn new(cratename: String, cfgs: Vec<String>, libs: SearchPaths, externs: Externs,
                use_headers: bool, opts: TestOptions, maybe_sysroot: Option<PathBuf>,
                codemap: Option<Lrc<CodeMap>>, filename: Option<PathBuf>,
-               linker: Option<PathBuf>) -> Collector {
+               linker: Option<PathBuf>, edition: Edition) -> Collector {
         Collector {
             tests: Vec::new(),
             names: Vec::new(),
@@ -488,6 +499,7 @@ impl Collector {
             codemap,
             filename,
             linker,
+            edition,
         }
     }
 
@@ -507,6 +519,7 @@ impl Collector {
         let opts = self.opts.clone();
         let maybe_sysroot = self.maybe_sysroot.clone();
         let linker = self.linker.clone();
+        let edition = self.edition;
         debug!("Creating test {}: {}", name, test);
         self.tests.push(testing::TestDescAndFn {
             desc: testing::TestDesc {
@@ -537,7 +550,8 @@ impl Collector {
                                  error_codes,
                                  &opts,
                                  maybe_sysroot,
-                                 linker)
+                                 linker,
+                                 edition)
                     }))
                 } {
                     Ok(()) => (),