Implement scope analysis and local variables (#3988)

* Remove unnecessary compile time environment clones

* Remove compile time environments from every runtime DeclarativeEnvironment

* Implement scope analysis and local variables

* fix docs and fuzzer errors

* Apply suggestions

* Align `parse_script` and `parse_module` arguments

* Fix fuzzer

cli/src/main.rs

@@ -190,8 +190,9 @@ where
         let mut parser = boa_parser::Parser::new(Source::from_bytes(src));
         let dump =
             if args.module {
+                let scope = context.realm().scope().clone();
                 let module = parser
-                    .parse_module(context.interner_mut())
+                    .parse_module(&scope, context.interner_mut())
                     .map_err(|e| format!("Uncaught SyntaxError: {e}"))?;
 
                 match arg {
@@ -202,8 +203,9 @@ where
                     DumpFormat::Debug => format!("{module:#?}"),
                 }
             } else {
+                let scope = context.realm().scope().clone();
                 let mut script = parser
-                    .parse_script(context.interner_mut())
+                    .parse_script(&scope, context.interner_mut())
                     .map_err(|e| format!("Uncaught SyntaxError: {e}"))?;
 
                 if args.optimize {

core/ast/Cargo.toml

@@ -11,12 +11,14 @@ repository.workspace = true
 rust-version.workspace = true
 
 [features]
+annex-b = []
 serde = ["dep:serde", "boa_interner/serde", "bitflags/serde", "num-bigint/serde"]
 arbitrary = ["dep:arbitrary", "boa_interner/arbitrary", "num-bigint/arbitrary"]
 
 [dependencies]
 boa_interner.workspace = true
 boa_macros.workspace = true
+boa_string.workspace = true
 rustc-hash = { workspace = true, features = ["std"] }
 bitflags.workspace = true
 num-bigint.workspace = true

core/ast/src/expression/literal/object.rs

@@ -8,8 +8,10 @@ use crate::{
     },
     function::{FormalParameterList, FunctionBody},
     join_nodes,
+    operations::{contains, ContainsSymbol},
     pattern::{ObjectPattern, ObjectPatternElement},
     property::{MethodDefinitionKind, PropertyName},
+    scope::FunctionScopes,
     try_break,
     visitor::{VisitWith, Visitor, VisitorMut},
 };
@@ -401,27 +403,35 @@ impl VisitWith for PropertyDefinition {
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, Debug, PartialEq)]
 pub struct ObjectMethodDefinition {
-    name: PropertyName,
-    parameters: FormalParameterList,
-    body: FunctionBody,
+    pub(crate) name: PropertyName,
+    pub(crate) parameters: FormalParameterList,
+    pub(crate) body: FunctionBody,
+    pub(crate) contains_direct_eval: bool,
     kind: MethodDefinitionKind,
+
+    #[cfg_attr(feature = "serde", serde(skip))]
+    pub(crate) scopes: FunctionScopes,
 }
 
 impl ObjectMethodDefinition {
     /// Creates a new object method definition.
     #[inline]
     #[must_use]
-    pub const fn new(
+    pub fn new(
         name: PropertyName,
         parameters: FormalParameterList,
         body: FunctionBody,
         kind: MethodDefinitionKind,
     ) -> Self {
+        let contains_direct_eval = contains(&parameters, ContainsSymbol::DirectEval)
+            || contains(&body, ContainsSymbol::DirectEval);
         Self {
             name,
             parameters,
             body,
+            contains_direct_eval,
             kind,
+            scopes: FunctionScopes::default(),
         }
     }
 
@@ -452,6 +462,13 @@ impl ObjectMethodDefinition {
     pub const fn kind(&self) -> MethodDefinitionKind {
         self.kind
     }
+
+    /// Gets the scopes of the object method definition.
+    #[inline]
+    #[must_use]
+    pub const fn scopes(&self) -> &FunctionScopes {
+        &self.scopes
+    }
 }
 
 impl ToIndentedString for ObjectMethodDefinition {
@@ -467,7 +484,7 @@ impl ToIndentedString for ObjectMethodDefinition {
         };
         let name = self.name.to_interned_string(interner);
         let parameters = join_nodes(interner, self.parameters.as_ref());
-        let body = block_to_string(self.body.statements(), interner, indent_n + 1);
+        let body = block_to_string(&self.body.statements, interner, indent_n + 1);
         format!("{indentation}{prefix}{name}({parameters}) {body},\n")
     }
 }
@@ -479,7 +496,7 @@ impl VisitWith for ObjectMethodDefinition {
     {
         try_break!(visitor.visit_property_name(&self.name));
         try_break!(visitor.visit_formal_parameter_list(&self.parameters));
-        visitor.visit_script(&self.body)
+        visitor.visit_function_body(&self.body)
     }
 
     fn visit_with_mut<'a, V>(&'a mut self, visitor: &mut V) -> ControlFlow<V::BreakTy>
@@ -488,6 +505,6 @@ impl VisitWith for ObjectMethodDefinition {
     {
         try_break!(visitor.visit_property_name_mut(&mut self.name));
         try_break!(visitor.visit_formal_parameter_list_mut(&mut self.parameters));
-        visitor.visit_script_mut(&mut self.body)
+        visitor.visit_function_body_mut(&mut self.body)
     }
 }

core/ast/src/function/arrow_function.rs

@@ -1,3 +1,5 @@
+use crate::operations::{contains, ContainsSymbol};
+use crate::scope::FunctionScopes;
 use crate::try_break;
 use crate::visitor::{VisitWith, Visitor, VisitorMut};
 use crate::{
@@ -23,34 +25,42 @@ use super::{FormalParameterList, FunctionBody};
 #[derive(Clone, Debug, PartialEq)]
 pub struct ArrowFunction {
     pub(crate) name: Option<Identifier>,
-    parameters: FormalParameterList,
-    body: FunctionBody,
+    pub(crate) parameters: FormalParameterList,
+    pub(crate) body: FunctionBody,
+    pub(crate) contains_direct_eval: bool,
+
+    #[cfg_attr(feature = "serde", serde(skip))]
+    pub(crate) scopes: FunctionScopes,
 }
 
 impl ArrowFunction {
     /// Creates a new `ArrowFunctionDecl` AST Expression.
     #[inline]
     #[must_use]
-    pub const fn new(
+    pub fn new(
         name: Option<Identifier>,
-        params: FormalParameterList,
+        parameters: FormalParameterList,
         body: FunctionBody,
     ) -> Self {
+        let contains_direct_eval = contains(&parameters, ContainsSymbol::DirectEval)
+            || contains(&body, ContainsSymbol::DirectEval);
         Self {
             name,
-            parameters: params,
+            parameters,
             body,
+            contains_direct_eval,
+            scopes: FunctionScopes::default(),
         }
     }
 
-    /// Gets the name of the function declaration.
+    /// Gets the name of the arrow function.
     #[inline]
     #[must_use]
     pub const fn name(&self) -> Option<Identifier> {
         self.name
     }
 
-    /// Sets the name of the function declaration.
+    /// Sets the name of the arrow function.
     #[inline]
     pub fn set_name(&mut self, name: Option<Identifier>) {
         self.name = name;
@@ -69,6 +79,13 @@ impl ArrowFunction {
     pub const fn body(&self) -> &FunctionBody {
         &self.body
     }
+
+    /// Returns the scopes of the arrow function.
+    #[inline]
+    #[must_use]
+    pub const fn scopes(&self) -> &FunctionScopes {
+        &self.scopes
+    }
 }
 
 impl ToIndentedString for ArrowFunction {
@@ -102,7 +119,7 @@ impl VisitWith for ArrowFunction {
             try_break!(visitor.visit_identifier(ident));
         }
         try_break!(visitor.visit_formal_parameter_list(&self.parameters));
-        visitor.visit_script(&self.body)
+        visitor.visit_function_body(&self.body)
     }
 
     fn visit_with_mut<'a, V>(&'a mut self, visitor: &mut V) -> ControlFlow<V::BreakTy>
@@ -113,6 +130,6 @@ impl VisitWith for ArrowFunction {
             try_break!(visitor.visit_identifier_mut(ident));
         }
         try_break!(visitor.visit_formal_parameter_list_mut(&mut self.parameters));
-        visitor.visit_script_mut(&mut self.body)
+        visitor.visit_function_body_mut(&mut self.body)
     }
 }

core/ast/src/function/async_arrow_function.rs

@@ -1,6 +1,8 @@
 use std::ops::ControlFlow;
 
 use super::{FormalParameterList, FunctionBody};
+use crate::operations::{contains, ContainsSymbol};
+use crate::scope::FunctionScopes;
 use crate::try_break;
 use crate::visitor::{VisitWith, Visitor, VisitorMut};
 use crate::{
@@ -23,52 +25,67 @@ use boa_interner::{Interner, ToIndentedString};
 #[derive(Clone, Debug, PartialEq)]
 pub struct AsyncArrowFunction {
     pub(crate) name: Option<Identifier>,
-    parameters: FormalParameterList,
-    body: FunctionBody,
+    pub(crate) parameters: FormalParameterList,
+    pub(crate) body: FunctionBody,
+    pub(crate) contains_direct_eval: bool,
+
+    #[cfg_attr(feature = "serde", serde(skip))]
+    pub(crate) scopes: FunctionScopes,
 }
 
 impl AsyncArrowFunction {
     /// Creates a new `AsyncArrowFunction` AST Expression.
     #[inline]
     #[must_use]
-    pub const fn new(
+    pub fn new(
         name: Option<Identifier>,
         parameters: FormalParameterList,
         body: FunctionBody,
     ) -> Self {
+        let contains_direct_eval = contains(&parameters, ContainsSymbol::DirectEval)
+            || contains(&body, ContainsSymbol::DirectEval);
         Self {
             name,
             parameters,
             body,
+            contains_direct_eval,
+            scopes: FunctionScopes::default(),
         }
     }
 
-    /// Gets the name of the function declaration.
+    /// Gets the name of the async arrow function.
     #[inline]
     #[must_use]
     pub const fn name(&self) -> Option<Identifier> {
         self.name
     }
 
-    /// Sets the name of the function declaration.
+    /// Sets the name of the async arrow function.
     #[inline]
     pub fn set_name(&mut self, name: Option<Identifier>) {
         self.name = name;
     }
 
-    /// Gets the list of parameters of the arrow function.
+    /// Gets the list of parameters of the async arrow function.
     #[inline]
     #[must_use]
     pub const fn parameters(&self) -> &FormalParameterList {
         &self.parameters
     }
 
-    /// Gets the body of the arrow function.
+    /// Gets the body of the async arrow function.
     #[inline]
     #[must_use]
     pub const fn body(&self) -> &FunctionBody {
         &self.body
     }
+
+    /// Returns the scopes of the async arrow function.
+    #[inline]
+    #[must_use]
+    pub const fn scopes(&self) -> &FunctionScopes {
+        &self.scopes
+    }
 }
 
 impl ToIndentedString for AsyncArrowFunction {
@@ -102,7 +119,7 @@ impl VisitWith for AsyncArrowFunction {
             try_break!(visitor.visit_identifier(ident));
         }
         try_break!(visitor.visit_formal_parameter_list(&self.parameters));
-        visitor.visit_script(&self.body)
+        visitor.visit_function_body(&self.body)
     }
 
     fn visit_with_mut<'a, V>(&'a mut self, visitor: &mut V) -> ControlFlow<V::BreakTy>
@@ -113,6 +130,6 @@ impl VisitWith for AsyncArrowFunction {
             try_break!(visitor.visit_identifier_mut(ident));
         }
         try_break!(visitor.visit_formal_parameter_list_mut(&mut self.parameters));
-        visitor.visit_script_mut(&mut self.body)
+        visitor.visit_function_body_mut(&mut self.body)
     }
 }