Report errors on invalid super usage in resolver

src/resolver/expr.rs

@@ -2,7 +2,7 @@ use std::sync::Arc;
 
 use miette::{NamedSource, SourceSpan};
 
-use super::{resolution_error::ResolutionError, Resolver, Result};
+use super::{resolution_error::ResolutionError, ClassType, Resolver, Result};
 use crate::ast::{
     expr::{Expr, ExprType::*},
     name::NameExpr,
@@ -73,15 +73,21 @@ impl Resolver {
         location: SourceSpan,
         src: &Arc<NamedSource<String>>,
     ) -> Result<()> {
-        // if self.current_class.is_none() {
-        //     Err(ResolutionError::InvalidThis {
-        //         src: src.clone(),
-        //         location,
-        //     })
-        // } else {
-        let name_expr = NameExpr::super_name(location, src.clone());
-        self.resolve_local(&name_expr);
-        Ok(())
-        // }
+        use ResolutionError::*;
+        match self.current_class {
+            None => Err(SuperOutsideClass {
+                src: src.clone(),
+                location,
+            }),
+            Some(ClassType::Class) => Err(SuperWithoutSuperclass {
+                src: src.clone(),
+                location,
+            }),
+            Some(ClassType::Subclass) => {
+                let name_expr = NameExpr::super_name(location, src.clone());
+                self.resolve_local(&name_expr);
+                Ok(())
+            }
+        }
     }
 }

src/resolver/mod.rs

@@ -29,6 +29,7 @@ enum FunctionType {
 #[derive(Debug)]
 enum ClassType {
     Class,
+    Subclass,
 }
 
 type Result<T> = std::result::Result<T, ResolutionError>;

src/resolver/resolution_error.rs

@@ -42,4 +42,20 @@ pub enum ResolutionError {
         #[label("here")]
         location: SourceSpan,
     },
+
+    #[error("Can't use 'super' outside of a class.")]
+    SuperOutsideClass {
+        #[source_code]
+        src: Arc<NamedSource<String>>,
+        #[label("here")]
+        location: SourceSpan,
+    },
+
+    #[error("Can't use 'super' in a class with no superclass")]
+    SuperWithoutSuperclass {
+        #[source_code]
+        src: Arc<NamedSource<String>>,
+        #[label("here")]
+        location: SourceSpan,
+    },
 }

src/resolver/statement.rs

@@ -74,7 +74,12 @@ impl Resolver {
         methods: &[Function],
         superclass: &Option<NameExpr>,
     ) -> Result<()> {
-        let enclosing_class = std::mem::replace(&mut self.current_class, Some(ClassType::Class));
+        let class_type = if superclass.is_some() {
+            ClassType::Subclass
+        } else {
+            ClassType::Class
+        };
+        let enclosing_class = std::mem::replace(&mut self.current_class, Some(class_type));
         self.declare(name);
         self.define(name);
 

tests/resolver_errors/super_outside_of_class.lox

@@ -0,0 +1,22 @@
+error
+super.a();
+----
+----
+{
+  "causes": [],
+  "filename": "tests/resolver_errors/super_outside_of_class.lox",
+  "labels": [
+    {
+      "label": "here",
+      "span": {
+        "length": 7,
+        "offset": 0
+      }
+    }
+  ],
+  "message": "Can't use 'super' outside of a class.",
+  "related": [],
+  "severity": "error"
+}
+----
+---- (no newline)

tests/resolver_errors/super_without_superclass.lox

@@ -0,0 +1,26 @@
+error
+class A {
+    method() {
+        super.x();
+    }
+}
+----
+----
+{
+  "causes": [],
+  "filename": "tests/resolver_errors/super_without_superclass.lox",
+  "labels": [
+    {
+      "label": "here",
+      "span": {
+        "length": 7,
+        "offset": 33
+      }
+    }
+  ],
+  "message": "Can't use 'super' in a class with no superclass",
+  "related": [],
+  "severity": "error"
+}
+----
+---- (no newline)