From 8329affbf8563d5440b4864e7860fc426959ddfe Mon Sep 17 00:00:00 2001
From: Edgar Luque <git@edgarluque.com>
Date: Mon, 4 Mar 2024 09:06:49 +0100
Subject: [PATCH] feat: more checks

---
 lib/edlang_check/src/lib.rs       | 10 ++++++++++
 lib/edlang_lowering/src/errors.rs |  2 ++
 lib/edlang_lowering/src/lib.rs    | 20 +++++++++++---------
 3 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/lib/edlang_check/src/lib.rs b/lib/edlang_check/src/lib.rs
index 3a21fffb4..ecfa1e477 100644
--- a/lib/edlang_check/src/lib.rs
+++ b/lib/edlang_check/src/lib.rs
@@ -126,5 +126,15 @@ pub fn lowering_error_to_report(
                 )
                 .finish()
         },
+        LoweringError::UseOfUndeclaredVariable { span, name } => {
+            Report::build(ReportKind::Error, path.clone(), span.lo)
+            .with_code("UseOfUndeclaredVariable")
+            .with_label(
+                Label::new((path, span.into()))
+                    .with_message(format!("use of undeclared variable {:?}", name))
+                    .with_color(colors.next()),
+            )
+            .finish()
+        },
     }
 }
diff --git a/lib/edlang_lowering/src/errors.rs b/lib/edlang_lowering/src/errors.rs
index a964e8ecf..b23a551c8 100644
--- a/lib/edlang_lowering/src/errors.rs
+++ b/lib/edlang_lowering/src/errors.rs
@@ -34,4 +34,6 @@ pub enum LoweringError {
         found: TypeKind,
         expected: TypeInfo,
     },
+    #[error("use of underclared variable {name:?}")]
+    UseOfUndeclaredVariable { span: Span, name: String },
 }
diff --git a/lib/edlang_lowering/src/lib.rs b/lib/edlang_lowering/src/lib.rs
index 7ac375a6b..b1e00646b 100644
--- a/lib/edlang_lowering/src/lib.rs
+++ b/lib/edlang_lowering/src/lib.rs
@@ -474,31 +474,31 @@ fn lower_let(builder: &mut BodyBuilder, info: &ast::LetStmt) -> Result<(), Lower
 
 fn lower_assign(builder: &mut BodyBuilder, info: &ast::AssignStmt) -> Result<(), LoweringError> {
     let (mut place, ty, _span) = lower_path(builder, &info.name)?;
-    let mut ty = TypeInfo {
+    let mut path_ty = TypeInfo {
         span: None,
         kind: ty,
     };
 
     for _ in 0..info.deref_times {
-        match &ty.kind {
+        match &path_ty.kind {
             TypeKind::Ptr(is_mut, inner) => {
                 if !is_mut {
                     panic!("trying to mutate non mut ptr");
                 }
-                ty = *inner.clone();
+                path_ty = *inner.clone();
             }
             TypeKind::Ref(is_mut, inner) => {
                 if !is_mut {
                     panic!("trying to mutate non mut ref");
                 }
-                ty = *inner.clone();
+                path_ty = *inner.clone();
             }
             _ => unreachable!(),
         }
         place.projection.push(PlaceElem::Deref);
     }
 
-    let (rvalue, _ty, _span) = lower_expr(builder, &info.value, Some(&ty))?;
+    let (rvalue, _ty, _span) = lower_expr(builder, &info.value, Some(&path_ty))?;
 
     builder.statements.push(Statement {
         span: Some(info.name.first.span),
@@ -1141,10 +1141,12 @@ fn lower_path(
     builder: &mut BodyBuilder,
     info: &ast::PathExpr,
 ) -> Result<(ir::Place, TypeKind, Span), LoweringError> {
-    let local = *builder
-        .name_to_local
-        .get(&info.first.name)
-        .expect("local not found");
+    let local = *builder.name_to_local.get(&info.first.name).ok_or(
+        LoweringError::UseOfUndeclaredVariable {
+            span: info.span,
+            name: info.first.name.clone(),
+        },
+    )?;
 
     let mut ty = builder.body.locals[local].ty.kind.clone();
     let mut projection = Vec::new();