feat: add mvp of unsafe blocks

aztec_macros/src/lib.rs

@@ -574,7 +574,7 @@ fn generate_storage_implementation(module: &mut SortedModule) -> Result<(), Azte
                 true,
             )),
         )],
-        &BlockExpression(vec![storage_constructor_statement]),
+        &BlockExpression { is_unsafe: false, statements: vec![storage_constructor_statement] },
         &[],
         &return_type(chained_path!("Self")),
     ));
@@ -609,25 +609,25 @@ fn transform_function(
     // Add access to the storage struct
     if storage_defined {
         let storage_def = abstract_storage(&ty.to_lowercase(), false);
-        func.def.body.0.insert(0, storage_def);
+        func.def.body.statements.insert(0, storage_def);
     }
 
     // Insert the context creation as the first action
     let create_context = create_context(&context_name, &func.def.parameters)?;
-    func.def.body.0.splice(0..0, (create_context).iter().cloned());
+    func.def.body.statements.splice(0..0, (create_context).iter().cloned());
 
     // Add the inputs to the params
     let input = create_inputs(&inputs_name);
     func.def.parameters.insert(0, input);
 
     // Abstract return types such that they get added to the kernel's return_values
     if let Some(return_values) = abstract_return_values(func) {
-        func.def.body.0.push(return_values);
+        func.def.body.statements.push(return_values);
     }
 
     // Push the finish method call to the end of the function
     let finish_def = create_context_finish();
-    func.def.body.0.push(finish_def);
+    func.def.body.statements.push(finish_def);
 
     let return_type = create_return_type(&return_type_name);
     func.def.return_type = return_type;
@@ -651,7 +651,7 @@ fn transform_vm_function(
 ) -> Result<(), AztecMacroError> {
     // Push Avm context creation to the beginning of the function
     let create_context = create_avm_context()?;
-    func.def.body.0.insert(0, create_context);
+    func.def.body.statements.insert(0, create_context);
 
     // We want the function to be seen as a public function
     func.def.is_open = true;
@@ -671,7 +671,7 @@ fn transform_vm_function(
 ///
 /// This will allow developers to access their contract' storage struct in unconstrained functions
 fn transform_unconstrained(func: &mut NoirFunction) {
-    func.def.body.0.insert(0, abstract_storage("Unconstrained", true));
+    func.def.body.statements.insert(0, abstract_storage("Unconstrained", true));
 }
 
 fn collect_crate_structs(crate_id: &CrateId, context: &HirContext) -> Vec<StructId> {
@@ -1002,10 +1002,15 @@ fn generate_selector_impl(structure: &NoirStruct) -> TypeImpl {
     let mut from_signature_path = selector_path.clone();
     from_signature_path.segments.push(ident("from_signature"));
 
-    let selector_fun_body = BlockExpression(vec![make_statement(StatementKind::Expression(call(
-        variable_path(from_signature_path),
-        vec![expression(ExpressionKind::Literal(Literal::Str(SIGNATURE_PLACEHOLDER.to_string())))],
-    )))]);
+    let selector_fun_body = BlockExpression {
+        is_unsafe: false,
+        statements: vec![make_statement(StatementKind::Expression(call(
+            variable_path(from_signature_path),
+            vec![expression(ExpressionKind::Literal(Literal::Str(
+                SIGNATURE_PLACEHOLDER.to_string(),
+            )))],
+        )))],
+    };
 
     // Define `FunctionSelector` return type
     let return_type =
@@ -1230,7 +1235,7 @@ fn create_avm_context() -> Result<Statement, AztecMacroError> {
 fn abstract_return_values(func: &NoirFunction) -> Option<Statement> {
     let current_return_type = func.return_type().typ;
     let len = func.def.body.len();
-    let last_statement = &func.def.body.0[len - 1];
+    let last_statement = &func.def.body.statements[len - 1];
 
     // TODO: (length, type) => We can limit the size of the array returned to be limited by kernel size
     // Doesn't need done until we have settled on a kernel size
@@ -1487,7 +1492,10 @@ fn create_loop_over(var: Expression, loop_body: Vec<Statement>) -> Statement {
 
     // What will be looped over
     // - `hasher.add({ident}[i] as Field)`
-    let for_loop_block = expression(ExpressionKind::Block(BlockExpression(loop_body)));
+    let for_loop_block = expression(ExpressionKind::Block(BlockExpression {
+        is_unsafe: false,
+        statements: loop_body,
+    }));
 
     // `for i in 0..{ident}.len()`
     make_statement(StatementKind::For(ForLoopStatement {

compiler/noirc_frontend/src/ast/expression.rs

@@ -180,16 +180,19 @@ impl Expression {
         // with tuples without calling them. E.g. `if c { t } else { e }(a, b)` is interpreted
         // as a sequence of { if, tuple } rather than a function call. This behavior matches rust.
         let kind = if matches!(&lhs.kind, ExpressionKind::If(..)) {
-            ExpressionKind::Block(BlockExpression(vec![
-                Statement { kind: StatementKind::Expression(lhs), span },
-                Statement {
-                    kind: StatementKind::Expression(Expression::new(
-                        ExpressionKind::Tuple(arguments),
+            ExpressionKind::Block(BlockExpression {
+                is_unsafe: false,
+                statements: vec![
+                    Statement { kind: StatementKind::Expression(lhs), span },
+                    Statement {
+                        kind: StatementKind::Expression(Expression::new(
+                            ExpressionKind::Tuple(arguments),
+                            span,
+                        )),
                         span,
-                    )),
-                    span,
-                },
-            ]))
+                    },
+                ],
+            })
         } else {
             ExpressionKind::Call(Box::new(CallExpression { func: Box::new(lhs), arguments }))
         };
@@ -456,19 +459,22 @@ pub struct IndexExpression {
 }
 
 #[derive(Debug, PartialEq, Eq, Clone)]
-pub struct BlockExpression(pub Vec<Statement>);
+pub struct BlockExpression {
+    pub is_unsafe: bool,
+    pub statements: Vec<Statement>,
+}
 
 impl BlockExpression {
     pub fn pop(&mut self) -> Option<StatementKind> {
-        self.0.pop().map(|stmt| stmt.kind)
+        self.statements.pop().map(|stmt| stmt.kind)
     }
 
     pub fn len(&self) -> usize {
-        self.0.len()
+        self.statements.len()
     }
 
     pub fn is_empty(&self) -> bool {
-        self.0.is_empty()
+        self.statements.is_empty()
     }
 }
 
@@ -537,8 +543,9 @@ impl Display for Literal {
 
 impl Display for BlockExpression {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        writeln!(f, "{{")?;
-        for statement in &self.0 {
+        let safety = if self.is_unsafe { "unsafe " } else { "" };
+        writeln!(f, "{safety}{{")?;
+        for statement in &self.statements {
             let statement = statement.kind.to_string();
             for line in statement.lines() {
                 writeln!(f, "    {line}")?;

compiler/noirc_frontend/src/ast/function.rs

@@ -83,7 +83,7 @@ impl NoirFunction {
         &mut self.def
     }
     pub fn number_of_statements(&self) -> usize {
-        self.def.body.0.len()
+        self.def.body.statements.len()
     }
     pub fn span(&self) -> Span {
         self.def.span

compiler/noirc_frontend/src/ast/statement.rs

@@ -588,10 +588,13 @@ impl ForRange {
                 };
 
                 let block_span = block.span;
-                let new_block = BlockExpression(vec![
-                    let_elem,
-                    Statement { kind: StatementKind::Expression(block), span: block_span },
-                ]);
+                let new_block = BlockExpression {
+                    is_unsafe: false,
+                    statements: vec![
+                        let_elem,
+                        Statement { kind: StatementKind::Expression(block), span: block_span },
+                    ],
+                };
                 let new_block = Expression::new(ExpressionKind::Block(new_block), block_span);
                 let for_loop = Statement {
                     kind: StatementKind::For(ForLoopStatement {
@@ -603,7 +606,10 @@ impl ForRange {
                     span: for_loop_span,
                 };
 
-                let block = ExpressionKind::Block(BlockExpression(vec![let_array, for_loop]));
+                let block = ExpressionKind::Block(BlockExpression {
+                    is_unsafe: false,
+                    statements: vec![let_array, for_loop],
+                });
                 StatementKind::Expression(Expression::new(block, for_loop_span))
             }
         }

compiler/noirc_frontend/src/debug/mod.rs

@@ -93,10 +93,10 @@ impl DebugInstrumenter {
             })
             .collect();
 
-        self.walk_scope(&mut func.body.0, func.span);
+        self.walk_scope(&mut func.body.statements, func.span);
 
         // prepend fn params:
-        func.body.0 = [set_fn_params, func.body.0.clone()].concat();
+        func.body.statements = [set_fn_params, func.body.statements.clone()].concat();
     }
 
     // Modify a vector of statements in-place, adding instrumentation for sets and drops.
@@ -212,7 +212,10 @@ impl DebugInstrumenter {
                 pattern: ast::Pattern::Tuple(vars_pattern, let_stmt.pattern.span()),
                 r#type: ast::UnresolvedType::unspecified(),
                 expression: ast::Expression {
-                    kind: ast::ExpressionKind::Block(ast::BlockExpression(block_stmts)),
+                    kind: ast::ExpressionKind::Block(ast::BlockExpression {
+                        is_unsafe: true,
+                        statements: block_stmts,
+                    }),
                     span: let_stmt.expression.span,
                 },
             }),
@@ -299,11 +302,14 @@ impl DebugInstrumenter {
             kind: ast::StatementKind::Assign(ast::AssignStatement {
                 lvalue: assign_stmt.lvalue.clone(),
                 expression: ast::Expression {
-                    kind: ast::ExpressionKind::Block(ast::BlockExpression(vec![
-                        ast::Statement { kind: let_kind, span: expression_span },
-                        new_assign_stmt,
-                        ast::Statement { kind: ret_kind, span: expression_span },
-                    ])),
+                    kind: ast::ExpressionKind::Block(ast::BlockExpression {
+                        is_unsafe: false,
+                        statements: vec![
+                            ast::Statement { kind: let_kind, span: expression_span },
+                            new_assign_stmt,
+                            ast::Statement { kind: ret_kind, span: expression_span },
+                        ],
+                    }),
                     span: expression_span,
                 },
             }),
@@ -313,7 +319,7 @@ impl DebugInstrumenter {
 
     fn walk_expr(&mut self, expr: &mut ast::Expression) {
         match &mut expr.kind {
-            ast::ExpressionKind::Block(ast::BlockExpression(ref mut statements)) => {
+            ast::ExpressionKind::Block(ast::BlockExpression { ref mut statements, .. }) => {
                 self.scope.push(HashMap::default());
                 self.walk_scope(statements, expr.span);
             }
@@ -384,14 +390,17 @@ impl DebugInstrumenter {
 
         self.walk_expr(&mut for_stmt.block);
         for_stmt.block = ast::Expression {
-            kind: ast::ExpressionKind::Block(ast::BlockExpression(vec![
-                set_stmt,
-                ast::Statement {
-                    kind: ast::StatementKind::Semi(for_stmt.block.clone()),
-                    span: for_stmt.block.span,
-                },
-                drop_stmt,
-            ])),
+            kind: ast::ExpressionKind::Block(ast::BlockExpression {
+                is_unsafe: false,
+                statements: vec![
+                    set_stmt,
+                    ast::Statement {
+                        kind: ast::StatementKind::Semi(for_stmt.block.clone()),
+                        span: for_stmt.block.span,
+                    },
+                    drop_stmt,
+                ],
+            }),
             span: for_stmt.span,
         };
     }
@@ -447,7 +456,9 @@ pub fn build_debug_crate_file() -> String {
                 __debug_var_assign_oracle(var_id, value);
             }
             pub fn __debug_var_assign<T>(var_id: u32, value: T) {
-                __debug_var_assign_inner(var_id, value);
+                unsafe {{
+                    __debug_var_assign_inner(var_id, value);
+                }}
             }
 
             #[oracle(__debug_var_drop)]
@@ -456,7 +467,9 @@ pub fn build_debug_crate_file() -> String {
                 __debug_var_drop_oracle(var_id);
             }
             pub fn __debug_var_drop<T>(var_id: u32) {
-                __debug_var_drop_inner(var_id);
+                unsafe {{
+                    __debug_var_drop_inner(var_id);
+                }}
             }
 
             #[oracle(__debug_dereference_assign)]
@@ -465,7 +478,9 @@ pub fn build_debug_crate_file() -> String {
                 __debug_dereference_assign_oracle(var_id, value);
             }
             pub fn __debug_dereference_assign<T>(var_id: u32, value: T) {
-                __debug_dereference_assign_inner(var_id, value);
+                unsafe {{
+                    __debug_dereference_assign_inner(var_id, value);
+                }}
             }
         "#
         .to_string(),
@@ -489,7 +504,9 @@ pub fn build_debug_crate_file() -> String {
                     __debug_oracle_member_assign_{n}(var_id, value, {vars});
                 }}
                 pub fn __debug_member_assign_{n}<T, Index>(var_id: u32, value: T, {var_sig}) {{
-                    __debug_inner_member_assign_{n}(var_id, value, {vars});
+                    unsafe {{
+                        __debug_inner_member_assign_{n}(var_id, value, {vars});
+                    }}
                 }}
 
             "#

compiler/noirc_frontend/src/hir/resolution/resolver.rs

@@ -244,7 +244,7 @@ impl<'a> Resolver<'a> {
                 typ: typ.clone(),
                 span: name.span(),
             }),
-            body: BlockExpression(Vec::new()),
+            body: BlockExpression { is_unsafe: false, statements: Vec::new() },
             span: name.span(),
             where_clause: where_clause.to_vec(),
             return_type: return_type.clone(),
@@ -1926,9 +1926,9 @@ impl<'a> Resolver<'a> {
     }
 
     fn resolve_block(&mut self, block_expr: BlockExpression) -> HirExpression {
-        let statements =
-            self.in_new_scope(|this| vecmap(block_expr.0, |stmt| this.intern_stmt(stmt.kind)));
-        HirExpression::Block(HirBlockExpression(statements))
+        let statements = self
+            .in_new_scope(|this| vecmap(block_expr.statements, |stmt| this.intern_stmt(stmt.kind)));
+        HirExpression::Block(HirBlockExpression { is_unsafe: block_expr.is_unsafe, statements })
     }
 
     pub fn intern_block(&mut self, block: BlockExpression) -> ExprId {

compiler/noirc_frontend/src/hir/type_check/errors.rs

@@ -122,6 +122,8 @@ pub enum TypeCheckError {
     ConstrainedReferenceToUnconstrained { span: Span },
     #[error("Slices cannot be returned from an unconstrained runtime to a constrained runtime")]
     UnconstrainedSliceReturnToConstrained { span: Span },
+    #[error("unsafe")]
+    Unsafe { span: Span },
 }
 
 impl TypeCheckError {
@@ -211,7 +213,7 @@ impl From<TypeCheckError> for Diagnostic {
             | TypeCheckError::OverflowingAssignment { span, .. }
             | TypeCheckError::FieldModulo { span }
             | TypeCheckError::ConstrainedReferenceToUnconstrained { span }
-            | TypeCheckError::UnconstrainedSliceReturnToConstrained { span } => {
+            | TypeCheckError::UnconstrainedSliceReturnToConstrained { span } | TypeCheckError::Unsafe { span } => {
                 Diagnostic::simple_error(error.to_string(), String::new(), span)
             }
             TypeCheckError::PublicReturnType { typ, span } => Diagnostic::simple_error(