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expand: Introduce enum for module loading errors and make module loading speculative

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This commit is contained in:
Vadim Petrochenkov 2021-02-22 21:22:40 +03:00
parent 1e1d574aea
commit 1fe2eb83ec
6 changed files with 91 additions and 92 deletions
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1
compiler/rustc_expand/src/lib.rs
View file

@ -1,3 +1,4 @@
#![feature(bool_to_option)]
#![feature(crate_visibility_modifier)]
#![feature(decl_macro)]
#![feature(destructuring_assignment)]

174
compiler/rustc_expand/src/module.rs
View file

@ -1,7 +1,7 @@
use crate::base::ModuleData;
use rustc_ast::ptr::P;
use rustc_ast::{token, Attribute, Item};
use rustc_errors::{struct_span_err, PResult};
use rustc_errors::{struct_span_err, DiagnosticBuilder};
use rustc_parse::new_parser_from_file;
use rustc_session::parse::ParseSess;
use rustc_session::Session;
@ -19,14 +19,6 @@ pub enum DirOwnership {
UnownedViaBlock,
}
/// Information about the path to a module.
// Public for rustfmt usage.
pub struct ModulePath<'a> {
name: String,
path_exists: bool,
pub result: PResult<'a, ModulePathSuccess>,
}
// Public for rustfmt usage.
pub struct ModulePathSuccess {
pub file_path: PathBuf,
@ -41,6 +33,14 @@ crate struct ParsedExternalMod {
pub dir_ownership: DirOwnership,
}
pub enum ModError<'a> {
CircularInclusion(Vec<PathBuf>),
ModInBlock(Option<Ident>),
FileNotFound(Ident, PathBuf),
MultipleCandidates(Ident, String, String),
ParserError(DiagnosticBuilder<'a>),
}
crate fn parse_external_mod(
sess: &Session,
ident: Ident,
@ -50,22 +50,26 @@ crate fn parse_external_mod(
attrs: &mut Vec<Attribute>,
) -> ParsedExternalMod {
// We bail on the first error, but that error does not cause a fatal error... (1)
let result: PResult<'_, _> = try {
let result: Result<_, ModError<'_>> = try {
// Extract the file path and the new ownership.
let mp = mod_file_path(sess, ident, span, &attrs, &module.dir_path, dir_ownership)?;
let mp = mod_file_path(sess, ident, &attrs, &module.dir_path, dir_ownership)?;
dir_ownership = mp.dir_ownership;
// Ensure file paths are acyclic.
error_on_circular_module(&sess.parse_sess, span, &mp.file_path, &module.file_path_stack)?;
if let Some(pos) = module.file_path_stack.iter().position(|p| p == &mp.file_path) {
Err(ModError::CircularInclusion(module.file_path_stack[pos..].to_vec()))?;
}
// Actually parse the external file as a module.
let mut parser = new_parser_from_file(&sess.parse_sess, &mp.file_path, Some(span));
let (mut inner_attrs, items, inner_span) = parser.parse_mod(&token::Eof)?;
let (mut inner_attrs, items, inner_span) =
parser.parse_mod(&token::Eof).map_err(|err| ModError::ParserError(err))?;
attrs.append(&mut inner_attrs);
(items, inner_span, mp.file_path)
};
// (1) ...instead, we return a dummy module.
let (items, inner_span, file_path) = result.map_err(|mut err| err.emit()).unwrap_or_default();
let (items, inner_span, file_path) =
result.map_err(|err| err.report(sess, span)).unwrap_or_default();
// Extract the directory path for submodules of the module.
let dir_path = file_path.parent().unwrap_or(&file_path).to_owned();
@ -73,24 +77,6 @@ crate fn parse_external_mod(
ParsedExternalMod { items, inner_span, file_path, dir_path, dir_ownership }
}
fn error_on_circular_module<'a>(
sess: &'a ParseSess,
span: Span,
file_path: &Path,
file_path_stack: &[PathBuf],
) -> PResult<'a, ()> {
if let Some(i) = file_path_stack.iter().position(|p| *p == file_path) {
let mut err = String::from("circular modules: ");
for p in &file_path_stack[i..] {
err.push_str(&p.to_string_lossy());
err.push_str(" -> ");
}
err.push_str(&file_path.to_string_lossy());
return Err(sess.span_diagnostic.struct_span_err(span, &err[..]));
}
Ok(())
}
crate fn mod_dir_path(
sess: &Session,
ident: Ident,
@ -125,11 +111,10 @@ crate fn mod_dir_path(
fn mod_file_path<'a>(
sess: &'a Session,
ident: Ident,
span: Span,
attrs: &[Attribute],
dir_path: &Path,
dir_ownership: DirOwnership,
) -> PResult<'a, ModulePathSuccess> {
) -> Result<ModulePathSuccess, ModError<'a>> {
if let Some(file_path) = mod_file_path_from_attr(sess, attrs, dir_path) {
// All `#[path]` files are treated as though they are a `mod.rs` file.
// This means that `mod foo;` declarations inside `#[path]`-included
@ -146,32 +131,16 @@ fn mod_file_path<'a>(
DirOwnership::Owned { relative } => relative,
DirOwnership::UnownedViaBlock => None,
};
let ModulePath { path_exists, name, result } =
default_submod_path(&sess.parse_sess, ident, span, relative, dir_path);
let result = default_submod_path(&sess.parse_sess, ident, relative, dir_path);
match dir_ownership {
DirOwnership::Owned { .. } => Ok(result?),
DirOwnership::UnownedViaBlock => {
let _ = result.map_err(|mut err| err.cancel());
error_decl_mod_in_block(&sess.parse_sess, span, path_exists, &name)
}
DirOwnership::Owned { .. } => result,
DirOwnership::UnownedViaBlock => Err(ModError::ModInBlock(match result {
Ok(_) | Err(ModError::MultipleCandidates(..)) => Some(ident),
_ => None,
})),
}
}
fn error_decl_mod_in_block<'a, T>(
sess: &'a ParseSess,
span: Span,
path_exists: bool,
name: &str,
) -> PResult<'a, T> {
let msg = "Cannot declare a non-inline module inside a block unless it has a path attribute";
let mut err = sess.span_diagnostic.struct_span_err(span, msg);
if path_exists {
let msg = format!("Maybe `use` the module `{}` instead of redeclaring it", name);
err.span_note(span, &msg);
}
Err(err)
}
/// Derive a submodule path from the first found `#[path = "path_string"]`.
/// The provided `dir_path` is joined with the `path_string`.
fn mod_file_path_from_attr(
@ -197,10 +166,9 @@ fn mod_file_path_from_attr(
pub fn default_submod_path<'a>(
sess: &'a ParseSess,
ident: Ident,
span: Span,
relative: Option<Ident>,
dir_path: &Path,
) -> ModulePath<'a> {
) -> Result<ModulePathSuccess, ModError<'a>> {
// If we're in a foo.rs file instead of a mod.rs file,
// we need to look for submodules in
// `./foo/<ident>.rs` and `./foo/<ident>/mod.rs` rather than
@ -222,7 +190,7 @@ pub fn default_submod_path<'a>(
let default_exists = sess.source_map().file_exists(&default_path);
let secondary_exists = sess.source_map().file_exists(&secondary_path);
let result = match (default_exists, secondary_exists) {
match (default_exists, secondary_exists) {
(true, false) => Ok(ModulePathSuccess {
file_path: default_path,
dir_ownership: DirOwnership::Owned { relative: Some(ident) },
@ -231,35 +199,65 @@ pub fn default_submod_path<'a>(
file_path: secondary_path,
dir_ownership: DirOwnership::Owned { relative: None },
}),
(false, false) => {
let mut err = struct_span_err!(
sess.span_diagnostic,
span,
E0583,
"file not found for module `{}`",
mod_name,
);
err.help(&format!(
"to create the module `{}`, create file \"{}\"",
mod_name,
default_path.display(),
));
Err(err)
}
(false, false) => Err(ModError::FileNotFound(ident, default_path)),
(true, true) => {
let mut err = struct_span_err!(
sess.span_diagnostic,
span,
E0761,
"file for module `{}` found at both {} and {}",
mod_name,
default_path_str,
secondary_path_str,
);
err.help("delete or rename one of them to remove the ambiguity");
Err(err)
Err(ModError::MultipleCandidates(ident, default_path_str, secondary_path_str))
}
};
ModulePath { name: mod_name, path_exists: default_exists || secondary_exists, result }
}
}
impl ModError<'_> {
fn report(self, sess: &Session, span: Span) {
let diag = &sess.parse_sess.span_diagnostic;
match self {
ModError::CircularInclusion(file_paths) => {
let mut msg = String::from("circular modules: ");
for file_path in &file_paths {
msg.push_str(&file_path.display().to_string());
msg.push_str(" -> ");
}
msg.push_str(&file_paths[0].display().to_string());
diag.struct_span_err(span, &msg)
}
ModError::ModInBlock(ident) => {
let msg = "cannot declare a non-inline module inside a block unless it has a path attribute";
let mut err = diag.struct_span_err(span, msg);
if let Some(ident) = ident {
let note =
format!("maybe `use` the module `{}` instead of redeclaring it", ident);
err.span_note(span, &note);
}
err
}
ModError::FileNotFound(ident, default_path) => {
let mut err = struct_span_err!(
diag,
span,
E0583,
"file not found for module `{}`",
ident,
);
err.help(&format!(
"to create the module `{}`, create file \"{}\"",
ident,
default_path.display(),
));
err
}
ModError::MultipleCandidates(ident, default_path_short, secondary_path_short) => {
let mut err = struct_span_err!(
diag,
span,
E0761,
"file for module `{}` found at both {} and {}",
ident,
default_path_short,
secondary_path_short,
);
err.help("delete or rename one of them to remove the ambiguity");
err
}
ModError::ParserError(err) => err,
}.emit()
}
}

2
src/test/ui/directory_ownership/macro-expanded-mod.rs
View file

@ -2,7 +2,7 @@
macro_rules! mod_decl {
($i:ident) => {
mod $i; //~ ERROR Cannot declare a non-inline module inside a block
mod $i; //~ ERROR cannot declare a non-inline module inside a block
};
}

2
src/test/ui/directory_ownership/macro-expanded-mod.stderr
View file

@ -1,4 +1,4 @@
error: Cannot declare a non-inline module inside a block unless it has a path attribute
error: cannot declare a non-inline module inside a block unless it has a path attribute
--> $DIR/macro-expanded-mod.rs:5:9
|
LL | mod $i;

2
src/test/ui/directory_ownership/non-inline-mod-restriction.rs
View file

@ -1,5 +1,5 @@
// Test that non-inline modules are not allowed inside blocks.
fn main() {
mod foo; //~ ERROR Cannot declare a non-inline module inside a block
mod foo; //~ ERROR cannot declare a non-inline module inside a block
}

2
src/test/ui/directory_ownership/non-inline-mod-restriction.stderr
View file

@ -1,4 +1,4 @@
error: Cannot declare a non-inline module inside a block unless it has a path attribute
error: cannot declare a non-inline module inside a block unless it has a path attribute
--> $DIR/non-inline-mod-restriction.rs:4:5
|
LL | mod foo;