Use panic to denote bugs in the check stage

src/check/constrain/constraint/builder.rs

@@ -4,9 +4,7 @@ use std::collections::HashMap;
 use crate::check::constrain::constraint::Constraint;
 use crate::check::constrain::constraint::expected::Expected;
 use crate::check::constrain::constraint::iterator::Constraints;
-use crate::check::result::{TypeErr, TypeResult};
 use crate::common::delimit::comma_delm;
-use crate::common::position::Position;
 
 pub type VarMapping = HashMap<String, usize>;
 
@@ -74,14 +72,15 @@ impl ConstrBuilder {
     ///
     /// - Error if already top-level.
     /// - Error if level greater than ceiling, as we cannot exit non-existent sets.
-    pub fn exit_set_to(&mut self, level: usize, pos: Position) -> TypeResult<()> {
+    pub fn exit_set_to(&mut self, level: usize) {
         let msg_exit = format!("Exit set to level {}", level - 1);
 
         let level = max(1, level);
         if level == 0 {
-            return Err(vec![TypeErr::new(pos, "Cannot exit top-level set")]);
+            panic!("Cannot exit top-level set");
         } else if level > self.constraints.len() {
-            return Err(vec![TypeErr::new(pos, "Exiting constraint set which doesn't exist")]);
+            panic!("Exiting constraint set which doesn't exist\nlevel: {}, constraints: {}, finished: {}",
+                   level, self.constraints.len(), self.finished.len());
         }
 
         for i in (level - 1..self.constraints.len()).rev() {
@@ -90,7 +89,6 @@ impl ConstrBuilder {
         }
 
         trace!("{msg_exit}: {} active sets, {} complete sets", self.constraints.len(), self.finished.len());
-        Ok(())
     }
 
     /// Add new constraint to constraint builder with a message.

src/check/constrain/generate/class.rs

@@ -57,6 +57,6 @@ pub fn constrain_class_body(
     let class_env = env.in_class(&name);
     gen_vec(statements, &class_env, true, ctx, constr)?;
 
-    constr.exit_set_to(class_lvl, ty.pos)?;
+    constr.exit_set_to(class_lvl);
     Ok(env.clone())
 }

src/check/constrain/generate/control_flow.rs

@@ -92,7 +92,7 @@ pub fn gen_flow(
             let lookup_env = gen_collection_lookup(expr, col, &col_env.is_def_mode(true), constr)?;
 
             generate(body, &lookup_env.in_loop().is_def_mode(is_define_mode), ctx, constr)?;
-            constr.exit_set_to(loop_lvl, ast.pos)?;
+            constr.exit_set_to(loop_lvl);
             Ok(env.clone())
         }
         Node::While { cond, body } => {
@@ -102,7 +102,7 @@ pub fn gen_flow(
 
             generate(cond, env, ctx, constr)?;
             generate(body, &env.in_loop(), ctx, constr)?;
-            constr.exit_set_to(while_lvl, ast.pos)?;
+            constr.exit_set_to(while_lvl);
             Ok(env.clone())
         }
 

src/check/constrain/generate/definition.rs

@@ -98,7 +98,7 @@ pub fn gen_def(
                 return Err(unassigned.iter().map(|msg| TypeErr::new(id.pos, msg)).collect());
             }
 
-            constr.exit_set_to(fun_lvl, ast.pos)?;
+            constr.exit_set_to(fun_lvl);
             Ok(env.clone())
         }
         Node::FunArg { .. } => {

src/check/constrain/generate/resources.rs

@@ -44,7 +44,7 @@ pub fn gen_resources(
             )?;
 
             generate(expr, &resource_env, ctx, constr)?;
-            constr.exit_set_to(with_lvl, ast.pos)?;
+            constr.exit_set_to(with_lvl);
             Ok(env.clone())
         }
         Node::With { resource, expr, .. } => {
@@ -57,7 +57,7 @@ pub fn gen_resources(
 
             let resource_env = generate(resource, env, ctx, constr)?;
 
-            constr.exit_set_to(with_lvl, ast.pos)?;
+            constr.exit_set_to(with_lvl);
             generate(expr, &resource_env, ctx, constr)?;
             Ok(env.clone())
         }