fix(lsp): replace panics with errors (#4209)

# Description

## Problem\*

Resolves <!-- Link to GitHub Issue -->

lsp panics when contract with #[event] #4203

## Summary\*

Replaces .expect calls with err returns.

## Additional Context



## Documentation\*

Check one:
- [x] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[Exceptional Case]** Documentation to be submitted in a separate
PR.

# PR Checklist\*

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

---------

Co-authored-by: jfecher <jake@aztecprotocol.com>

aztec_macros/src/lib.rs

@@ -26,8 +26,12 @@ impl MacroProcessor for AztecMacro {
         transform(ast, crate_id, context)
     }
 
-    fn process_typed_ast(&self, crate_id: &CrateId, context: &mut HirContext) {
-        transform_hir(crate_id, context)
+    fn process_typed_ast(
+        &self,
+        crate_id: &CrateId,
+        context: &mut HirContext,
+    ) -> Result<(), (MacroError, FileId)> {
+        transform_hir(crate_id, context).map_err(|(err, file_id)| (err.into(), file_id))
     }
 }
 
@@ -41,6 +45,7 @@ pub enum AztecMacroError {
     ContractHasTooManyFunctions { span: Span },
     ContractConstructorMissing { span: Span },
     UnsupportedFunctionArgumentType { span: Span, typ: UnresolvedTypeData },
+    EventError { span: Span, message: String },
 }
 
 impl From<AztecMacroError> for MacroError {
@@ -71,6 +76,11 @@ impl From<AztecMacroError> for MacroError {
                 secondary_message: None,
                 span: Some(span),
             },
+            AztecMacroError::EventError { span, message } => MacroError {
+                primary_message: message,
+                secondary_message: None,
+                span: Some(span),
+            },
         }
     }
 }
@@ -237,8 +247,11 @@ fn transform(
 //
 
 /// Completes the Hir with data gathered from type resolution
-fn transform_hir(crate_id: &CrateId, context: &mut HirContext) {
-    transform_events(crate_id, context);
+fn transform_hir(
+    crate_id: &CrateId,
+    context: &mut HirContext,
+) -> Result<(), (AztecMacroError, FileId)> {
+    transform_events(crate_id, context)
 }
 
 /// Includes an import to the aztec library if it has not been included yet
@@ -472,19 +485,30 @@ fn collect_crate_structs(crate_id: &CrateId, context: &HirContext) -> Vec<Struct
 }
 
 /// Substitutes the signature literal that was introduced in the selector method previously with the actual signature.
-fn transform_event(struct_id: StructId, interner: &mut NodeInterner) {
+fn transform_event(
+    struct_id: StructId,
+    interner: &mut NodeInterner,
+) -> Result<(), (AztecMacroError, FileId)> {
     let struct_type = interner.get_struct(struct_id);
     let selector_id = interner
-        .lookup_method(&Type::Struct(struct_type, vec![]), struct_id, "selector", false)
-        .expect("Selector method not found");
+        .lookup_method(&Type::Struct(struct_type.clone(), vec![]), struct_id, "selector", false)
+        .ok_or_else(|| {
+            let error = AztecMacroError::EventError {
+                span: struct_type.borrow().location.span,
+                message: "Selector method not found".to_owned(),
+            };
+            (error, struct_type.borrow().location.file)
+        })?;
     let selector_function = interner.function(&selector_id);
 
     let compute_selector_statement = interner.statement(
-        selector_function
-            .block(interner)
-            .statements()
-            .first()
-            .expect("Compute selector statement not found"),
+        selector_function.block(interner).statements().first().ok_or_else(|| {
+            let error = AztecMacroError::EventError {
+                span: struct_type.borrow().location.span,
+                message: "Compute selector statement not found".to_owned(),
+            };
+            (error, struct_type.borrow().location.file)
+        })?,
     );
 
     let compute_selector_expression = match compute_selector_statement {
@@ -494,12 +518,21 @@ fn transform_event(struct_id: StructId, interner: &mut NodeInterner) {
         },
         _ => None,
     }
-    .expect("Compute selector statement is not a call expression");
-
-    let first_arg_id = compute_selector_expression
-        .arguments
-        .first()
-        .expect("Missing argument for compute selector");
+    .ok_or_else(|| {
+        let error = AztecMacroError::EventError {
+            span: struct_type.borrow().location.span,
+            message: "Compute selector statement is not a call expression".to_owned(),
+        };
+        (error, struct_type.borrow().location.file)
+    })?;
+
+    let first_arg_id = compute_selector_expression.arguments.first().ok_or_else(|| {
+        let error = AztecMacroError::EventError {
+            span: struct_type.borrow().location.span,
+            message: "Compute selector statement is not a call expression".to_owned(),
+        };
+        (error, struct_type.borrow().location.file)
+    })?;
 
     match interner.expression(first_arg_id) {
         HirExpression::Literal(HirLiteral::Str(signature))
@@ -518,18 +551,29 @@ fn transform_event(struct_id: StructId, interner: &mut NodeInterner) {
                 selector_literal_id,
                 Type::String(Box::new(Type::Constant(signature.len() as u64))),
             );
+            Ok(())
         }
-        _ => unreachable!("Signature placeholder literal does not match"),
+        _ => Err((
+            AztecMacroError::EventError {
+                span: struct_type.borrow().location.span,
+                message: "Signature placeholder literal does not match".to_owned(),
+            },
+            struct_type.borrow().location.file,
+        )),
     }
 }
 
-fn transform_events(crate_id: &CrateId, context: &mut HirContext) {
+fn transform_events(
+    crate_id: &CrateId,
+    context: &mut HirContext,
+) -> Result<(), (AztecMacroError, FileId)> {
     for struct_id in collect_crate_structs(crate_id, context) {
         let attributes = context.def_interner.struct_attributes(&struct_id);
         if attributes.iter().any(|attr| matches!(attr, SecondaryAttribute::Event)) {
-            transform_event(struct_id, &mut context.def_interner);
+            transform_event(struct_id, &mut context.def_interner)?;
         }
     }
+    Ok(())
 }
 
 const SIGNATURE_PLACEHOLDER: &str = "SIGNATURE_PLACEHOLDER";

compiler/noirc_frontend/src/hir/def_collector/dc_crate.rs

@@ -14,7 +14,7 @@ use crate::hir::resolution::{
 use crate::hir::type_check::{type_check_func, TypeCheckError, TypeChecker};
 use crate::hir::Context;
 
-use crate::macros_api::MacroProcessor;
+use crate::macros_api::{MacroError, MacroProcessor};
 use crate::node_interner::{FuncId, NodeInterner, StmtId, StructId, TraitId, TypeAliasId};
 
 use crate::parser::{ParserError, SortedModule};
@@ -155,6 +155,12 @@ impl From<CompilationError> for CustomDiagnostic {
     }
 }
 
+impl From<MacroError> for CompilationError {
+    fn from(value: MacroError) -> Self {
+        CompilationError::DefinitionError(DefCollectorErrorKind::MacroError(value))
+    }
+}
+
 impl From<ParserError> for CompilationError {
     fn from(value: ParserError) -> Self {
         CompilationError::ParseError(value)
@@ -359,7 +365,11 @@ impl DefCollector {
         errors.extend(resolved_globals.errors);
 
         for macro_processor in macro_processors {
-            macro_processor.process_typed_ast(&crate_id, context);
+            macro_processor.process_typed_ast(&crate_id, context).unwrap_or_else(
+                |(macro_err, file_id)| {
+                    errors.push((macro_err.into(), file_id));
+                },
+            );
         }
         errors.extend(type_check_globals(&mut context.def_interner, resolved_globals.globals));
 

compiler/noirc_frontend/src/lib.rs

@@ -75,6 +75,10 @@ pub mod macros_api {
         ) -> Result<SortedModule, (MacroError, FileId)>;
         /// Function to manipulate the AST after type checking has been completed.
         /// The AST after type checking has been done is called the HIR.
-        fn process_typed_ast(&self, crate_id: &CrateId, context: &mut HirContext);
+        fn process_typed_ast(
+            &self,
+            crate_id: &CrateId,
+            context: &mut HirContext,
+        ) -> Result<(), (MacroError, FileId)>;
     }
 }