Parser: Error recovery (#449)

Implement some error recovery logic to parser

.vscode/settings.json

@@ -1,20 +1,23 @@
 {
-    "files.exclude": {
-        "**/.git": true,
-        "**/.svn": true,
-        "**/.hg": true,
-        "**/CVS": true,
-        "**/.DS_Store": true,
-        "**/*.bk": true,
-    },
-    "[rust]": {
-        "editor.formatOnSave": true
-    },
-    "rust.rustflags": "--cfg procmacro2_semver_exempt",
-    // Important
-    "rust.cfg_test": false,
-    "rust-client.revealOutputChannelOn": "warn",
-    "rust-client.logToFile": true,
-    "editor.formatOnSave": true,
-
-}
+  "files.exclude": {
+    "**/.git": true,
+    "**/.svn": true,
+    "**/.hg": true,
+    "**/CVS": true,
+    "**/.DS_Store": true,
+    "**/*.bk": true
+  },
+  "[rust]": {
+    "editor.formatOnSave": true
+  },
+  "[typescript]": {
+    "editor.formatOnSave": false
+  },
+  "rust.rustflags": "--cfg procmacro2_semver_exempt",
+  // Important
+  "rust.cfg_test": false,
+  "rust-client.revealOutputChannelOn": "warn",
+  "rust-client.logToFile": true,
+  "editor.formatOnSave": true,
+  "git.ignoreLimitWarning": true
+}

Cargo.toml

@@ -19,13 +19,13 @@ swc_common = { path ="./common" }
 swc_ecmascript = { path ="./ecmascript" }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
-sourcemap = "2"
 failure = "0.1"
 path-clean = "0.1"
 lazy_static = "1"
 hashbrown = "0.5"
 regex = "1"
 chashmap = "2.2.2"
+sourcemap = "2.2"
 
 [[example]]
 name = "usage"
@@ -34,6 +34,7 @@ name = "usage"
 lto = true
 
 [profile.release]
+codegen-units = 1
 lto = true
 
 [patch.crates-io]

atoms/words.txt

@@ -38,6 +38,7 @@ BiquadFilterNode
 Blob
 BlobEvent
 Boolean
+Bottom line
 BroadcastChannel
 BudgetService
 ByteLengthQueuingStrategy
@@ -113,6 +114,8 @@ EvalError
 Event
 EventSource
 EventTarget
+Exclude
+Extract
 File
 FileList
 FileReader
@@ -289,6 +292,7 @@ Node
 NodeFilter
 NodeIterator
 NodeList
+NonNullable
 Notification
 Number
 Object
@@ -299,6 +303,7 @@ Option
 OscillatorNode
 PageTransitionEvent
 PannerNode
+Partial
 Path2D
 PaymentAddress
 PaymentRequest
@@ -320,6 +325,7 @@ PeriodicWave
 PermissionStatus
 Permissions
 PhotoCapabilities
+Pick
 Plugin
 PluginArray
 PointerEvent
@@ -361,14 +367,19 @@ Range
 RangeError
 React
 ReadableStream
+Readonly
+ReadonlyArray
+Record
 ReferenceError
 Reflect
 RegExp
 RemotePlayback
 Request
+Required
 ResizeObserver
 ResizeObserverEntry
 Response
+ReturnType
 SVGAElement
 SVGAngle
 SVGAnimateElement
@@ -565,6 +576,7 @@ abstract
 any
 apply
 arguments
+arguments
 as
 async
 await
@@ -590,6 +602,7 @@ do
 else
 enum
 env
+eval
 export
 extends
 false
@@ -635,8 +648,8 @@ switch
 symbol
 target
 this
-this
 throw
+toString
 true
 try
 type

common/src/errors/mod.rs

@@ -22,7 +22,7 @@ use crate::{
 use hashbrown::HashSet;
 use std::{
     borrow::Cow,
-    cell::Cell,
+    cell::RefCell,
     error, fmt, panic,
     sync::{
         atomic::{AtomicUsize, Ordering::SeqCst},
@@ -293,8 +293,8 @@ pub struct Handler {
 
 fn default_track_diagnostic(_: &Diagnostic) {}
 
-thread_local!(pub static TRACK_DIAGNOSTICS: Cell<fn(&Diagnostic)> =
-                Cell::new(default_track_diagnostic));
+thread_local!(pub static TRACK_DIAGNOSTICS: RefCell<Box<dyn Fn(&Diagnostic)>> =
+                RefCell::new(Box::new(default_track_diagnostic)));
 
 #[derive(Default)]
 pub struct HandlerFlags {
@@ -716,7 +716,7 @@ impl Handler {
         let diagnostic = &**db;
 
         TRACK_DIAGNOSTICS.with(|track_diagnostics| {
-            track_diagnostics.get()(diagnostic);
+            track_diagnostics.borrow()(diagnostic);
         });
 
         if let Some(ref code) = diagnostic.code {

common/src/fold/mod.rs

@@ -1,6 +1,7 @@
 use self::and_then::AndThen;
 use crate::util::{map::Map, move_map::MoveMap};
 use either::Either;
+use std::{borrow::Cow, sync::Arc};
 use string_cache::{Atom, StaticAtomSet};
 
 pub mod and_then;
@@ -282,3 +283,33 @@ where
         }
     }
 }
+
+impl<T, F> VisitWith<F> for Arc<T>
+where
+    T: ?Sized,
+    F: Visit<T>,
+{
+    fn visit_children(&self, f: &mut F) {
+        f.visit(&**self)
+    }
+}
+
+impl<'a, A, F> FoldWith<F> for Cow<'a, A>
+where
+    A: Clone + FoldWith<F>,
+{
+    /// `#[inline(always)]`: To optimize .into_owned()
+    #[inline(always)]
+    fn fold_children(self, f: &mut F) -> Self {
+        Cow::Owned(self.into_owned().fold_with(f))
+    }
+}
+
+impl<A, F> VisitWith<F> for Cow<'_, A>
+where
+    A: Clone + VisitWith<F>,
+{
+    fn visit_children(&self, f: &mut F) {
+        (**self).visit_children(f)
+    }
+}

common/src/pos.rs

@@ -5,6 +5,7 @@ pub use crate::syntax_pos::{
     SourceFile, SourceFileAndBytePos, SourceFileAndLine, Span, SpanData, SpanLinesError,
     SyntaxContext, CM, DUMMY_SP, GLOBALS, NO_EXPANSION,
 };
+use std::{borrow::Cow, sync::Arc};
 
 ///
 /// # Derive
@@ -14,6 +15,16 @@ pub trait Spanned {
     fn span(&self) -> Span;
 }
 
+impl<'a, T> Spanned for Cow<'a, T>
+where
+    T: Spanned + Clone,
+{
+    #[inline(always)]
+    fn span(&self) -> Span {
+        (**self).span()
+    }
+}
+
 impl Spanned for Span {
     #[inline(always)]
     fn span(&self) -> Span {
@@ -41,6 +52,15 @@ where
     }
 }
 
+impl<S> Spanned for Arc<S>
+where
+    S: ?Sized + Spanned,
+{
+    fn span(&self) -> Span {
+        <S as Spanned>::span(&*self)
+    }
+}
+
 impl<S> Spanned for Box<S>
 where
     S: ?Sized + Spanned,

common/src/util/iter.rs

@@ -0,0 +1,48 @@
+pub trait IteratorExt: Iterator {
+    /// Copied from https://stackoverflow.com/a/49456265/6193633
+    fn chain_with<F, I>(self, f: F) -> ChainWith<Self, F, I::IntoIter>
+    where
+        Self: Sized,
+        F: FnOnce() -> I,
+        I: IntoIterator<Item = Self::Item>,
+    {
+        ChainWith {
+            base: self,
+            factory: Some(f),
+            iterator: None,
+        }
+    }
+}
+
+impl<I: Iterator> IteratorExt for I {}
+
+pub struct ChainWith<B, F, I> {
+    base: B,
+    factory: Option<F>,
+    iterator: Option<I>,
+}
+
+impl<B, F, I> Iterator for ChainWith<B, F, I::IntoIter>
+where
+    B: Iterator,
+    F: FnOnce() -> I,
+    I: IntoIterator<Item = B::Item>,
+{
+    type Item = I::Item;
+    fn next(&mut self) -> Option<Self::Item> {
+        if let Some(b) = self.base.next() {
+            return Some(b);
+        }
+
+        // Exhausted the first, generate the second
+
+        if let Some(f) = self.factory.take() {
+            self.iterator = Some(f().into_iter());
+        }
+
+        self.iterator
+            .as_mut()
+            .expect("There must be an iterator")
+            .next()
+    }
+}

common/src/util/mod.rs

@@ -1,2 +1,3 @@
+pub mod iter;
 pub mod map;
 pub mod move_map;

ecmascript/Cargo.toml

@@ -14,6 +14,5 @@ swc_ecma_ast = { path ="./ast" }
 swc_ecma_codegen = { path ="./codegen" }
 swc_ecma_parser = { path ="./parser", features = ["verify"] }
 swc_ecma_transforms = { path ="./transforms" }
-swc_ecma_lints = { path ="./lints" }
 
 [dev-dependencies]

ecmascript/ast/src/expr.rs

@@ -13,6 +13,7 @@ use crate::{
         TsAsExpr, TsConstAssertion, TsNonNullExpr, TsOptChain, TsTypeAnn, TsTypeAssertion,
         TsTypeCastExpr, TsTypeParamDecl, TsTypeParamInstantiation,
     },
+    Invalid,
 };
 use serde::{self, Deserialize, Serialize};
 #[cfg(feature = "fold")]
@@ -144,6 +145,9 @@ pub enum Expr {
 
     #[tag("TsOptionalChainingExpression")]
     TsOptChain(TsOptChain),
+
+    #[tag("Invalid")]
+    Invalid(Invalid),
 }
 
 #[ast_node("ThisExpression")]

ecmascript/ast/src/lib.rs

@@ -41,7 +41,10 @@ pub use self::{
     pat::{
         ArrayPat, AssignPat, AssignPatProp, KeyValuePatProp, ObjectPat, ObjectPatProp, Pat, RestPat,
     },
-    prop::{AssignProp, GetterProp, KeyValueProp, MethodProp, Prop, PropName, SetterProp},
+    prop::{
+        AssignProp, ComputedPropName, GetterProp, KeyValueProp, MethodProp, Prop, PropName,
+        SetterProp,
+    },
     stmt::{
         BlockStmt, BreakStmt, CatchClause, ContinueStmt, DebuggerStmt, DoWhileStmt, EmptyStmt,
         ForInStmt, ForOfStmt, ForStmt, IfStmt, LabeledStmt, ReturnStmt, Stmt, SwitchCase,
@@ -64,6 +67,7 @@ pub use self::{
         TsUnionOrIntersectionType, TsUnionType,
     },
 };
+use swc_common::{ast_node, Span};
 
 #[macro_use]
 mod macros;
@@ -81,3 +85,10 @@ mod pat;
 mod prop;
 mod stmt;
 mod typescript;
+
+/// Represents a invalid node.
+#[ast_node("Invalid")]
+#[derive(Copy)]
+pub struct Invalid {
+    pub span: Span,
+}

ecmascript/ast/src/pat.rs

@@ -1,4 +1,4 @@
-use crate::{expr::Expr, ident::Ident, prop::PropName, typescript::TsTypeAnn};
+use crate::{expr::Expr, ident::Ident, prop::PropName, typescript::TsTypeAnn, Invalid};
 use swc_common::{ast_node, Span};
 
 #[ast_node]
@@ -18,6 +18,9 @@ pub enum Pat {
     #[tag("AssignmentPattern")]
     Assign(AssignPat),
 
+    #[tag("Invalid")]
+    Invalid(Invalid),
+
     /// Only for for-in / for-of loops. This is *syntatically* valid.
     #[tag("*")]
     Expr(Box<Expr>),