diff --git a/Cargo.lock b/Cargo.lock
index 8c4ba59a..941a6816 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1745,7 +1745,6 @@ dependencies = [
 name = "rue-diagnostic"
 version = "0.6.0"
 dependencies = [
- "derive_more",
  "thiserror 2.0.14",
 ]
 
@@ -1838,13 +1837,13 @@ dependencies = [
  "chialisp",
  "clvmr",
  "env_logger",
+ "indexmap",
  "rue-compiler",
  "rue-diagnostic",
  "rue-lir",
  "rue-options",
  "serde",
  "serde_yml",
- "walkdir",
 ]
 
 [[package]]
@@ -1921,15 +1920,6 @@ version = "1.0.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "28d3b2b1366ec20994f1fd18c3c594f05c5dd4bc44d8bb0c1c632c8d6829481f"
 
-[[package]]
-name = "same-file"
-version = "1.0.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
-dependencies = [
- "winapi-util",
-]
-
 [[package]]
 name = "scopeguard"
 version = "1.2.0"
@@ -2514,16 +2504,6 @@ version = "0.9.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
 
-[[package]]
-name = "walkdir"
-version = "2.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "29790946404f91d9c5d06f9874efddea1dc06c5efe94541a7d6863108e3a5e4b"
-dependencies = [
- "same-file",
- "winapi-util",
-]
-
 [[package]]
 name = "wasi"
 version = "0.11.1+wasi-snapshot-preview1"
@@ -2600,15 +2580,6 @@ dependencies = [
  "unicode-ident",
 ]
 
-[[package]]
-name = "winapi-util"
-version = "0.1.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf221c93e13a30d793f7645a0e7762c55d169dbb0a49671918a2319d289b10bb"
-dependencies = [
- "windows-sys 0.59.0",
-]
-
 [[package]]
 name = "windows-link"
 version = "0.1.3"
diff --git a/crates/rue-cli/src/main.rs b/crates/rue-cli/src/main.rs
index 3f1af41f..aaa5cfb1 100644
--- a/crates/rue-cli/src/main.rs
+++ b/crates/rue-cli/src/main.rs
@@ -135,11 +135,16 @@ fn build(args: BuildArgs) -> Result<()> {
     let mut ctx = Compiler::new(project.options);
 
     let tree = FileTree::compile_path(&mut ctx, &project.entrypoint, &mut HashMap::new())?;
+    let base_path = if project.entrypoint.is_file() {
+        project.entrypoint.parent().unwrap().canonicalize()?
+    } else {
+        project.entrypoint.canonicalize()?
+    };
 
     let mut codegen = true;
 
     for diagnostic in ctx.take_diagnostics() {
-        let message = diagnostic.message();
+        let message = diagnostic.message(&base_path);
         let severity = diagnostic.kind.severity();
 
         if severity == DiagnosticSeverity::Error {
@@ -156,7 +161,13 @@ fn build(args: BuildArgs) -> Result<()> {
 
     let program = if let Some(export) = args.export {
         let Some(program) = tree
-            .exports(&mut ctx, &mut allocator, file_kind.as_ref(), Some(&export))?
+            .exports(
+                &mut ctx,
+                &mut allocator,
+                file_kind.as_ref(),
+                Some(&export),
+                &base_path,
+            )?
             .into_iter()
             .next()
         else {
@@ -166,7 +177,7 @@ fn build(args: BuildArgs) -> Result<()> {
 
         program.ptr
     } else if let Some(main_kind) = main_kind
-        && let Some(ptr) = tree.main(&mut ctx, &mut allocator, &main_kind)?
+        && let Some(ptr) = tree.main(&mut ctx, &mut allocator, &main_kind, base_path)?
     {
         ptr
     } else {
@@ -210,11 +221,16 @@ fn test(args: TestArgs) -> Result<()> {
     let mut ctx = Compiler::new(project.options);
 
     let tree = FileTree::compile_path(&mut ctx, &project.entrypoint, &mut HashMap::new())?;
+    let base_path = if project.entrypoint.is_file() {
+        project.entrypoint.parent().unwrap().canonicalize()?
+    } else {
+        project.entrypoint.canonicalize()?
+    };
 
     let mut codegen = true;
 
     for diagnostic in ctx.take_diagnostics() {
-        let message = diagnostic.message();
+        let message = diagnostic.message(&base_path);
         let severity = diagnostic.kind.severity();
 
         if severity == DiagnosticSeverity::Error {
@@ -229,7 +245,7 @@ fn test(args: TestArgs) -> Result<()> {
         process::exit(1);
     }
 
-    let tests = tree.tests(&mut ctx, &mut allocator, None, None)?;
+    let tests = tree.tests(&mut ctx, &mut allocator, None, None, &base_path)?;
 
     let len = tests.len();
 
diff --git a/crates/rue-compiler/src/compile/path.rs b/crates/rue-compiler/src/compile/path.rs
index 84735595..87c4d0b3 100644
--- a/crates/rue-compiler/src/compile/path.rs
+++ b/crates/rue-compiler/src/compile/path.rs
@@ -362,6 +362,15 @@ where
             );
             PathResult::Unresolved
         }
+        (PathResult::Symbol(symbol, _, _), PathKind::Symbol) => {
+            if let Symbol::Module(_) = ctx.symbol(symbol) {
+                ctx.diagnostic(
+                    range,
+                    DiagnosticKind::CannotReferenceModule(previous_name.unwrap()),
+                );
+            }
+            value
+        }
         _ => value,
     }
 }
diff --git a/crates/rue-compiler/src/file.rs b/crates/rue-compiler/src/file.rs
index 48c470a9..b4a16718 100644
--- a/crates/rue-compiler/src/file.rs
+++ b/crates/rue-compiler/src/file.rs
@@ -1,7 +1,7 @@
 use std::{
     collections::{HashMap, HashSet},
     fs, io,
-    path::Path,
+    path::{Path, PathBuf},
     sync::Arc,
 };
 
@@ -32,7 +32,7 @@ pub enum Error {
     #[error("Codegen error: {0}")]
     Lir(#[from] rue_lir::Error),
 
-    #[error("Source not found in compilation unit: {0}")]
+    #[error("Source not found in compilation unit")]
     SourceNotFound(SourceKind),
 }
 
@@ -58,14 +58,11 @@ pub enum FileTree {
 }
 
 impl FileTree {
-    pub fn compile_file(ctx: &mut Compiler, path: &Path, file_name: String) -> Result<Self, Error> {
+    pub fn compile_file(ctx: &mut Compiler, path: &Path) -> Result<Self, Error> {
         let tree = Self::File(File::new(
             ctx,
             "main".to_string(),
-            Source::new(
-                Arc::from(fs::read_to_string(path)?),
-                SourceKind::File(file_name),
-            ),
+            Source::new(Arc::from(fs::read_to_string(path)?), normalize_path(path)?),
         ));
 
         tree.compile(ctx);
@@ -250,6 +247,7 @@ impl FileTree {
         ctx: &mut Compiler,
         allocator: &mut Allocator,
         path: &SourceKind,
+        base_path: PathBuf,
     ) -> Result<Option<NodePtr>, Error> {
         let tree = self
             .find(path)
@@ -260,7 +258,7 @@ impl FileTree {
             return Ok(None);
         };
 
-        Ok(Some(codegen(ctx, allocator, main)?))
+        Ok(Some(codegen(ctx, allocator, main, base_path)?))
     }
 
     pub fn exports(
@@ -269,12 +267,21 @@ impl FileTree {
         allocator: &mut Allocator,
         path: Option<&SourceKind>,
         export_name: Option<&str>,
+        base_path: &Path,
     ) -> Result<Vec<CompiledExport>, Error> {
         let Some(path) = path else {
             return Ok(self
                 .all_files()
                 .iter()
-                .map(|file| self.exports(ctx, allocator, Some(&file.source.kind), export_name))
+                .map(|file| {
+                    self.exports(
+                        ctx,
+                        allocator,
+                        Some(&file.source.kind),
+                        export_name,
+                        base_path,
+                    )
+                })
                 .collect::<Result<Vec<_>, Error>>()?
                 .into_iter()
                 .flatten()
@@ -301,7 +308,7 @@ impl FileTree {
                 continue;
             }
 
-            let ptr = codegen(ctx, allocator, symbol)?;
+            let ptr = codegen(ctx, allocator, symbol, base_path.to_path_buf())?;
             exports.push(CompiledExport { name, symbol, ptr });
         }
 
@@ -314,6 +321,7 @@ impl FileTree {
         allocator: &mut Allocator,
         path: Option<&SourceKind>,
         search_term: Option<&str>,
+        base_path: &Path,
     ) -> Result<Vec<CompiledTest>, Error> {
         let tests = ctx
             .tests()
@@ -340,7 +348,7 @@ impl FileTree {
         let mut outputs = Vec::new();
 
         for test in tests {
-            let ptr = codegen(ctx, allocator, test.symbol)?;
+            let ptr = codegen(ctx, allocator, test.symbol, base_path.to_path_buf())?;
             outputs.push(CompiledTest {
                 name: test.name,
                 path: test.path,
@@ -635,12 +643,13 @@ fn codegen(
     ctx: &mut Compiler,
     allocator: &mut Allocator,
     symbol: SymbolId,
+    base_path: PathBuf,
 ) -> Result<NodePtr, Error> {
     let options = *ctx.options();
     let graph = DependencyGraph::build(ctx, symbol, options);
 
     let mut arena = Arena::new();
-    let mut lowerer = Lowerer::new(ctx, &mut arena, &graph, options, symbol);
+    let mut lowerer = Lowerer::new(ctx, &mut arena, &graph, options, symbol, base_path);
     let mut lir = lowerer.lower_symbol_value(&Environment::default(), symbol);
 
     if options.optimize_lir {
diff --git a/crates/rue-diagnostic/Cargo.toml b/crates/rue-diagnostic/Cargo.toml
index e5757cb8..470cbd7b 100644
--- a/crates/rue-diagnostic/Cargo.toml
+++ b/crates/rue-diagnostic/Cargo.toml
@@ -16,4 +16,3 @@ workspace = true
 
 [dependencies]
 thiserror = { workspace = true }
-derive_more = { workspace = true, features = ["display"] }
diff --git a/crates/rue-diagnostic/src/diagnostic.rs b/crates/rue-diagnostic/src/diagnostic.rs
index 77c31f4b..306e2d72 100644
--- a/crates/rue-diagnostic/src/diagnostic.rs
+++ b/crates/rue-diagnostic/src/diagnostic.rs
@@ -1,3 +1,5 @@
+use std::path::Path;
+
 use crate::{DiagnosticKind, LineCol, SrcLoc};
 
 #[derive(Debug, Clone)]
@@ -19,9 +21,14 @@ impl Diagnostic {
         self.srcloc.end()
     }
 
-    pub fn message(&self) -> String {
+    pub fn message(&self, relative_to: &Path) -> String {
         let start = self.start();
 
-        format!("{} at {}:{}", self.kind, self.srcloc.source.kind, start)
+        format!(
+            "{} at {}:{}",
+            self.kind,
+            self.srcloc.source.kind.display(relative_to),
+            start
+        )
     }
 }
diff --git a/crates/rue-diagnostic/src/kind.rs b/crates/rue-diagnostic/src/kind.rs
index d12aa180..6e19d145 100644
--- a/crates/rue-diagnostic/src/kind.rs
+++ b/crates/rue-diagnostic/src/kind.rs
@@ -129,6 +129,9 @@ pub enum DiagnosticKind {
     #[error("Expected type, but found symbol `{0}`")]
     ExpectedType(String),
 
+    #[error("Cannot reference module `{0}`")]
+    CannotReferenceModule(String),
+
     #[error("Generic arguments are not permitted on symbol references")]
     GenericArgumentsOnSymbolReference,
 
@@ -269,6 +272,7 @@ impl DiagnosticKind {
             | Self::PrivateType(..)
             | Self::ExpectedSymbol(..)
             | Self::ExpectedType(..)
+            | Self::CannotReferenceModule(..)
             | Self::GenericArgumentsOnSymbolReference
             | Self::NonStructInitializer(..)
             | Self::MissingRequiredFields(..)
diff --git a/crates/rue-diagnostic/src/srcloc.rs b/crates/rue-diagnostic/src/srcloc.rs
index 29e59e85..46688bcb 100644
--- a/crates/rue-diagnostic/src/srcloc.rs
+++ b/crates/rue-diagnostic/src/srcloc.rs
@@ -1,6 +1,4 @@
-use std::{fmt, ops::Range, sync::Arc};
-
-use derive_more::Display;
+use std::{ops::Range, path::Path, sync::Arc};
 
 use crate::LineCol;
 
@@ -16,12 +14,9 @@ impl Source {
     }
 }
 
-#[derive(Debug, Clone, Display, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum SourceKind {
-    #[display("std")]
     Std,
-
-    #[display("{_0}")]
     File(String),
 }
 
@@ -32,6 +27,15 @@ impl SourceKind {
             Self::File(_) => true,
         }
     }
+
+    pub fn display(&self, relative_to: &Path) -> String {
+        match self {
+            Self::Std => "std".to_string(),
+            Self::File(path) => Path::new(path)
+                .strip_prefix(relative_to)
+                .map_or_else(|_| path.clone(), |path| path.to_string_lossy().to_string()),
+        }
+    }
 }
 
 #[derive(Debug, Clone)]
@@ -52,10 +56,8 @@ impl SrcLoc {
     pub fn end(&self) -> LineCol {
         LineCol::new(&self.source.text, self.span.end)
     }
-}
 
-impl fmt::Display for SrcLoc {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{}:{}", self.source.kind, self.start())
+    pub fn display(&self, relative_to: &Path) -> String {
+        format!("{}:{}", self.source.kind.display(relative_to), self.start())
     }
 }
diff --git a/crates/rue-hir/src/lower.rs b/crates/rue-hir/src/lower.rs
index ef72e520..a8bce4e8 100644
--- a/crates/rue-hir/src/lower.rs
+++ b/crates/rue-hir/src/lower.rs
@@ -1,6 +1,6 @@
 #![allow(clippy::needless_pass_by_value)]
 
-use std::{collections::HashMap, mem};
+use std::{collections::HashMap, mem, path::PathBuf};
 
 use id_arena::Arena;
 use indexmap::{IndexMap, IndexSet};
@@ -38,6 +38,7 @@ pub struct Lowerer<'d, 'a, 'g> {
     inline_symbols: Vec<HashMap<SymbolId, HirId>>,
     options: CompilerOptions,
     main: SymbolId,
+    base_path: PathBuf,
 }
 
 impl<'d, 'a, 'g> Lowerer<'d, 'a, 'g> {
@@ -47,6 +48,7 @@ impl<'d, 'a, 'g> Lowerer<'d, 'a, 'g> {
         graph: &'g DependencyGraph,
         options: CompilerOptions,
         main: SymbolId,
+        base_path: PathBuf,
     ) -> Self {
         Self {
             db,
@@ -55,6 +57,7 @@ impl<'d, 'a, 'g> Lowerer<'d, 'a, 'g> {
             inline_symbols: Vec::new(),
             options,
             main,
+            base_path,
         }
     }
 
@@ -704,7 +707,9 @@ impl<'d, 'a, 'g> Lowerer<'d, 'a, 'g> {
         }
 
         let value = self.lower_hir(env, value);
-        let print = self.arena.alloc(Lir::DebugPrint(srcloc.to_string(), value));
+        let print = self
+            .arena
+            .alloc(Lir::DebugPrint(srcloc.display(&self.base_path), value));
         let nil = self.arena.alloc(Lir::Atom(vec![]));
         self.arena.alloc(Lir::If(print, nil, rest, false))
     }
diff --git a/crates/rue-parser/src/grammar.rs b/crates/rue-parser/src/grammar.rs
index 5ba987db..a6f6fd1c 100644
--- a/crates/rue-parser/src/grammar.rs
+++ b/crates/rue-parser/src/grammar.rs
@@ -11,7 +11,7 @@ pub(crate) use document::document;
 
 #[cfg(test)]
 mod tests {
-    use std::sync::Arc;
+    use std::{path::Path, sync::Arc};
 
     use expect_test::Expect;
     use rue_diagnostic::{Source, SourceKind};
@@ -38,7 +38,7 @@ mod tests {
             if i != 0 {
                 error_output.push('\n');
             }
-            error_output.push_str(&error.message());
+            error_output.push_str(&error.message(Path::new(".")));
         }
 
         expect.assert_eq(&output);
diff --git a/crates/rue-tests/Cargo.toml b/crates/rue-tests/Cargo.toml
index b97ae18e..9412a5f2 100644
--- a/crates/rue-tests/Cargo.toml
+++ b/crates/rue-tests/Cargo.toml
@@ -24,6 +24,6 @@ clvmr = { workspace = true }
 chialisp = { workspace = true }
 anyhow = { workspace = true }
 serde = { workspace = true }
-walkdir = { workspace = true }
 serde_yml = { workspace = true }
 env_logger = { workspace = true }
+indexmap = { workspace = true }
diff --git a/crates/rue-tests/src/main.rs b/crates/rue-tests/src/main.rs
index ba354480..c2a55bdf 100644
--- a/crates/rue-tests/src/main.rs
+++ b/crates/rue-tests/src/main.rs
@@ -1,3 +1,4 @@
+use std::collections::HashMap;
 use std::env;
 use std::fs;
 use std::path::Path;
@@ -10,12 +11,13 @@ use clvmr::{
     Allocator, ChiaDialect, ENABLE_KECCAK_OPS_OUTSIDE_GUARD, MEMPOOL_MODE, NodePtr, run_program,
     serde::node_to_bytes,
 };
+use indexmap::IndexMap;
+use rue_compiler::normalize_path;
 use rue_compiler::{Compiler, FileTree};
-use rue_diagnostic::{DiagnosticSeverity, SourceKind};
+use rue_diagnostic::DiagnosticSeverity;
 use rue_lir::DebugDialect;
 use rue_options::CompilerOptions;
 use serde::{Deserialize, Serialize};
-use walkdir::{DirEntry, WalkDir};
 
 #[derive(Debug, Default, Clone, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(default)]
@@ -76,7 +78,7 @@ fn main() -> Result<()> {
     let args: Vec<String> = env::args().collect();
     let filter_arg = args.get(1).cloned();
 
-    let failed = run_tests(filter_arg.as_deref(), ".", true)?;
+    let failed = run_tests(filter_arg.as_deref(), Path::new("."), true)?;
 
     if failed {
         process::exit(1);
@@ -85,16 +87,31 @@ fn main() -> Result<()> {
     Ok(())
 }
 
-fn run_tests(filter_arg: Option<&str>, base_path: &str, update: bool) -> Result<bool> {
+fn run_tests(filter_arg: Option<&str>, base_path: &Path, update: bool) -> Result<bool> {
     let mut failed = false;
 
-    for entry in WalkDir::new(Path::new(base_path).join("tests"))
-        .into_iter()
-        .chain(WalkDir::new(Path::new(base_path).join("examples")).into_iter())
-    {
+    walk_dir(&base_path.join("tests"), filter_arg, update, &mut failed)?;
+    walk_dir(&base_path.join("examples"), filter_arg, update, &mut failed)?;
+
+    Ok(failed)
+}
+
+fn walk_dir(path: &Path, filter_arg: Option<&str>, update: bool, failed: &mut bool) -> Result<()> {
+    let mut directories = IndexMap::new();
+
+    for entry in fs::read_dir(path)? {
         let entry = entry?;
+        let path = entry.path();
 
-        if let Some(name) = entry.file_name().to_str().unwrap().strip_suffix(".rue") {
+        if path.is_dir() {
+            directories.insert(entry.file_name().to_string_lossy().to_string(), path);
+            continue;
+        }
+
+        let file_name = entry.file_name();
+        let file_name = file_name.to_str().unwrap();
+
+        if let Some(name) = file_name.strip_suffix(".rue") {
             if !entry
                 .path()
                 .parent()
@@ -102,15 +119,28 @@ fn run_tests(filter_arg: Option<&str>, base_path: &str, update: bool) -> Result<
                 .join(format!("{name}.yaml"))
                 .try_exists()?
             {
-                handle_test_file(name, &entry, &mut failed, update)?;
+                handle_test_file(name, &entry.path(), failed, update, false)?;
             }
             continue;
         }
 
-        let Some(name) = entry.file_name().to_str().unwrap().strip_suffix(".yaml") else {
+        let Some(name) = file_name.strip_suffix(".yaml") else {
             continue;
         };
 
+        let mut is_dir = false;
+
+        if !entry
+            .path()
+            .parent()
+            .unwrap()
+            .join(format!("{name}.rue"))
+            .try_exists()?
+        {
+            directories.shift_remove(name);
+            is_dir = true;
+        }
+
         // If a filter argument is provided, skip tests that don't contain it
         if let Some(ref filter) = filter_arg
             && !name.contains(filter)
@@ -118,16 +148,25 @@ fn run_tests(filter_arg: Option<&str>, base_path: &str, update: bool) -> Result<
             continue;
         }
 
-        handle_test_file(name, &entry, &mut failed, update)?;
+        handle_test_file(name, &entry.path(), failed, update, is_dir)?;
     }
 
-    Ok(failed)
+    for (_, path) in directories {
+        walk_dir(&path, filter_arg, update, failed)?;
+    }
+
+    Ok(())
 }
 
-fn handle_test_file(name: &str, entry: &DirEntry, failed: &mut bool, update: bool) -> Result<()> {
-    let parent = entry.path().parent().unwrap();
+fn handle_test_file(
+    name: &str,
+    entry: &Path,
+    failed: &mut bool,
+    update: bool,
+    is_dir: bool,
+) -> Result<()> {
+    let parent = entry.parent().unwrap();
     let yaml_file = parent.join(format!("{name}.yaml"));
-    let rue_file = parent.join(format!("{name}.rue"));
 
     println!("Running {name}");
 
@@ -144,16 +183,26 @@ fn handle_test_file(name: &str, entry: &DirEntry, failed: &mut bool, update: boo
     let mut ctx = Compiler::new(CompilerOptions::default());
     let mut debug_ctx = Compiler::new(CompilerOptions::debug());
 
-    let unit = FileTree::compile_file(&mut ctx, &rue_file, "test".to_string())?;
-    let debug_unit = FileTree::compile_file(&mut debug_ctx, &rue_file, "test".to_string())?;
-    let kind = SourceKind::File("test".to_string());
+    let (unit, debug_unit, kind, base_path) = if is_dir {
+        let rue_dir = parent.join(name);
+        let unit = FileTree::compile_path(&mut ctx, &rue_dir, &mut HashMap::new())?;
+        let debug_unit = FileTree::compile_path(&mut debug_ctx, &rue_dir, &mut HashMap::new())?;
+        let kind = normalize_path(&rue_dir.join("main.rue"))?;
+        (unit, debug_unit, kind, rue_dir.canonicalize()?)
+    } else {
+        let rue_file = parent.join(format!("{name}.rue"));
+        let unit = FileTree::compile_file(&mut ctx, &rue_file)?;
+        let debug_unit = FileTree::compile_file(&mut debug_ctx, &rue_file)?;
+        let kind = normalize_path(&rue_file)?;
+        (unit, debug_unit, kind, parent.canonicalize()?)
+    };
 
     file.diagnostics = Vec::new();
 
     let mut codegen = true;
 
     for diagnostic in ctx.take_diagnostics() {
-        file.diagnostics.push(diagnostic.message());
+        file.diagnostics.push(diagnostic.message(&base_path));
 
         if diagnostic.kind.severity() == DiagnosticSeverity::Error {
             codegen = false;
@@ -161,20 +210,20 @@ fn handle_test_file(name: &str, entry: &DirEntry, failed: &mut bool, update: boo
     }
 
     let main = codegen
-        .then(|| unit.main(&mut ctx, &mut allocator, &kind))
+        .then(|| unit.main(&mut ctx, &mut allocator, &kind, base_path.clone()))
         .transpose()?
         .flatten();
     let debug_main = codegen
-        .then(|| debug_unit.main(&mut debug_ctx, &mut allocator, &kind))
+        .then(|| debug_unit.main(&mut debug_ctx, &mut allocator, &kind, base_path.clone()))
         .transpose()?
         .flatten();
 
     let tests = codegen
-        .then(|| unit.tests(&mut ctx, &mut allocator, None, None))
+        .then(|| unit.tests(&mut ctx, &mut allocator, None, None, &base_path))
         .transpose()?
         .unwrap_or_default();
     let debug_tests = codegen
-        .then(|| debug_unit.tests(&mut debug_ctx, &mut allocator, None, None))
+        .then(|| debug_unit.tests(&mut debug_ctx, &mut allocator, None, None, &base_path))
         .transpose()?
         .unwrap_or_default();
 
@@ -313,7 +362,7 @@ mod tests {
 
     #[test]
     fn tests() -> Result<()> {
-        let failed = run_tests(None, "../..", false)?;
+        let failed = run_tests(None, Path::new("../.."), false)?;
 
         assert!(!failed);
 
diff --git a/examples/brainfck.yaml b/examples/brainfck.yaml
index 32688006..3e7f3238 100644
--- a/examples/brainfck.yaml
+++ b/examples/brainfck.yaml
@@ -1,7 +1,7 @@
 tests:
 - name: abc
   program: (a (q 5 (r (r (f (a 12 (c (c 8 (c 12 (c 22 30))) (c (c (c () (c () (c () ()))) (c () (c () ()))) (c (concat (a 10 (c 10 (c (q . 43) (q . 65)))) (q . ".+.+.")) ())))))))) (c (c (c (q 2 (i 7 (q 2 (q 16 (a (i (= 6 (q . 91)) (q 2 5 (c 5 (c (+ 11 (q . 1)) 4))) (q 2 (i (= 6 (q . 93)) (q 2 (i (= 11 (q . 1)) (q) (q 2 5 (c 5 (c (- 11 (q . 1)) 4)))) 1) (q 2 5 (c 5 (c 11 4)))) 1)) 1) (q . 1)) (c (c (substr 7 (q . 1)) (substr 7 () (q . 1))) 1)) (q)) 1) (q 2 (i 11 (q 2 10 (c (c 4 (c 10 (c 22 30))) (a 30 (c (c 4 (c 10 (c 22 30))) 3)))) (q . 3)) 1)) (c (q 2 (i (> 7 ()) (q 14 5 (a 2 (c 2 (c 5 (- 7 (q . 1)))))) (q)) 1) (c (q 2 (i 17 (q 2 22 (c (c 4 (c 10 (c 22 30))) (c (f (a 10 (c (c 4 (c 10 (c 22 30))) (c 5 (c 7 ()))))) 7))) (q . 5)) 1) (q 2 (q 2 (i (= 6 (q . 43)) (q 4 (c (c (+ 35 (q . 1)) (c 83 (c -77 ()))) (c 43 (c 91 ()))) (c 4 ())) (q 2 (i (= 6 (q . 45)) (q 4 (c (c (- 35 (q . 1)) (c 83 (c -77 ()))) (c 43 (c 91 ()))) (c 4 ())) (q 2 (i (= 6 (q . 60)) (q 4 (a (i 83 (q 4 (c -109 (c -45 (c (c 35 -77) ()))) (c 43 (c 91 ()))) (q 4 (c () (c () (c (c 35 -77) ()))) (c 43 (c 91 ())))) 1) (c 4 ())) (q 2 (i (= 6 (q . 62)) (q 4 (a (i -77 (q 4 (c 307 (c (c 35 83) (c 435 ()))) (c 43 (c 91 ()))) (q 4 (c () (c (c 35 83) (c () ()))) (c 43 (c 91 ())))) 1) (c 4 ())) (q 2 (i (= 6 (q . 44)) (q 4 (c (c (substr 43 () (q . 1)) (c 83 (c -77 ()))) (c (substr 43 (q . 1)) (c 91 ()))) (c 4 ())) (q 2 (i (= 6 (q . 46)) (q 4 (c 19 (c 43 (c (concat 91 35) ()))) (c 4 ())) (q 2 (i (= 6 (q . 91)) (q 2 (q 4 (a 91 (c (c 19 (c 43 (c 91 123))) (c 23 (substr 9 () 2)))) (c (substr 9 2) ())) (c (a 9 (c 9 (c (q . 1) 4))) 1)) (q 4 11 (c 4 ()))) 1)) 1)) 1)) 1)) 1)) 1)) 1) (c (c (substr 11 (q . 1)) (substr 11 () (q . 1))) 1))))) ()))
-  debug_program: (a (q 2 (q 2 (q 2 (i ("debug_print" (q . "test:207:5") (concat (concat (concat (concat (concat (concat (q . "run(`") (concat (a 43 (c 43 (c (q . 43) (q . 65)))) (q . ".+.+."))) (q . "`, `")) ()) (q . "`) = `")) 2) (q . 96))) (q) (q . 2)) 1) (c (f (r (r (f (a 25 (c (c 17 (c 25 (c 45 61))) 2)))))) 1)) (c (c (c (c () (c () (c () ()))) (c () (c () ()))) (c (concat (a 10 (c 10 (c (q . 43) (q . 65)))) (q . ".+.+.")) ())) 1)) (c (c (c (q 2 (i (= 7 ()) (q) (q 2 (q 16 (q . 1) (a (i (= 6 (q . 91)) (q 2 5 (c 5 (c (+ 11 (q . 1)) 4))) (q 2 (i (= 6 (q . 93)) (q 2 (i (= 11 (q . 1)) (q) (q 2 5 (c 5 (c (- 11 (q . 1)) 4)))) 1) (q 2 5 (c 5 (c 11 4)))) 1)) 1)) (c (c (substr 7 (q . 1)) (substr 7 () (q . 1))) 1))) 1) (q 2 (i (= (f (r 3)) ()) (q . 3) (q 2 10 (c (c 4 (c 10 (c 22 30))) (a 30 (c (c 4 (c 10 (c 22 30))) 3))))) 1)) (c (q 2 (i (> 7 ()) (q 14 5 (a 2 (c 2 (c 5 (- 7 (q . 1)))))) (q)) 1) (c (q 2 (i (= (f (f 5)) ()) (q . 5) (q 2 22 (c (c 4 (c 10 (c 22 30))) (c (f (a 10 (c (c 4 (c 10 (c 22 30))) (c 5 (c 7 ()))))) 7)))) 1) (q 2 (q 2 (i (= 6 (q . 43)) (q 4 (c (c (+ (f (f (f 7))) (q . 1)) (c (f (r (f (f 7)))) (c (f (r (r (f (f 7))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 45)) (q 4 (c (c (- (f (f (f 7))) (q . 1)) (c (f (r (f (f 7)))) (c (f (r (r (f (f 7))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 60)) (q 4 (a (i (not (l (f (r (f (f 7)))))) (q 4 (c () (c () (c (c (f (f (f 7))) (f (r (r (f (f 7)))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (q 4 (c (f (f (r (f (f 7))))) (c (r (f (r (f (f 7))))) (c (c (f (f (f 7))) (f (r (r (f (f 7)))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ())))) 1) (c 4 ())) (q 2 (i (= 6 (q . 62)) (q 4 (a (i (not (l (f (r (r (f (f 7))))))) (q 4 (c () (c (c (f (f (f 7))) (f (r (f (f 7))))) (c () ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (q 4 (c (f (f (r (r (f (f 7)))))) (c (c (f (f (f 7))) (f (r (f (f 7))))) (c (r (f (r (r (f (f 7)))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ())))) 1) (c 4 ())) (q 2 (i (= 6 (q . 44)) (q 4 (c (c (substr (f (r (f 7))) () (q . 1)) (c (f (r (f (f 7)))) (c (f (r (r (f (f 7))))) ()))) (c (substr (f (r (f 7))) (q . 1)) (c (f (r (r (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 46)) (q 4 (c (f (f 7)) (c (f (r (f 7))) (c (concat (f (r (r (f 7)))) (f (f (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 91)) (q 2 (q 2 (q 4 (a -73 (c (c 39 (c 87 (c -73 -9))) (c (f 31) 4))) (c 6 ())) (c (c (substr 9 () 2) (substr 9 2)) 1)) (c (a 9 (c 9 (c (q . 1) 4))) 1)) (q 4 (f 7) (c 4 ()))) 1)) 1)) 1)) 1)) 1)) 1)) 1) (c (c (substr (f (r 3)) (q . 1)) (substr (f (r 3)) () (q . 1))) 1))))) ()))
+  debug_program: (a (q 2 (q 2 (q 2 (i ("debug_print" (q . "brainfck.rue:207:5") (concat (concat (concat (concat (concat (concat (q . "run(`") (concat (a 43 (c 43 (c (q . 43) (q . 65)))) (q . ".+.+."))) (q . "`, `")) ()) (q . "`) = `")) 2) (q . 96))) (q) (q . 2)) 1) (c (f (r (r (f (a 25 (c (c 17 (c 25 (c 45 61))) 2)))))) 1)) (c (c (c (c () (c () (c () ()))) (c () (c () ()))) (c (concat (a 10 (c 10 (c (q . 43) (q . 65)))) (q . ".+.+.")) ())) 1)) (c (c (c (q 2 (i (= 7 ()) (q) (q 2 (q 16 (q . 1) (a (i (= 6 (q . 91)) (q 2 5 (c 5 (c (+ 11 (q . 1)) 4))) (q 2 (i (= 6 (q . 93)) (q 2 (i (= 11 (q . 1)) (q) (q 2 5 (c 5 (c (- 11 (q . 1)) 4)))) 1) (q 2 5 (c 5 (c 11 4)))) 1)) 1)) (c (c (substr 7 (q . 1)) (substr 7 () (q . 1))) 1))) 1) (q 2 (i (= (f (r 3)) ()) (q . 3) (q 2 10 (c (c 4 (c 10 (c 22 30))) (a 30 (c (c 4 (c 10 (c 22 30))) 3))))) 1)) (c (q 2 (i (> 7 ()) (q 14 5 (a 2 (c 2 (c 5 (- 7 (q . 1)))))) (q)) 1) (c (q 2 (i (= (f (f 5)) ()) (q . 5) (q 2 22 (c (c 4 (c 10 (c 22 30))) (c (f (a 10 (c (c 4 (c 10 (c 22 30))) (c 5 (c 7 ()))))) 7)))) 1) (q 2 (q 2 (i (= 6 (q . 43)) (q 4 (c (c (+ (f (f (f 7))) (q . 1)) (c (f (r (f (f 7)))) (c (f (r (r (f (f 7))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 45)) (q 4 (c (c (- (f (f (f 7))) (q . 1)) (c (f (r (f (f 7)))) (c (f (r (r (f (f 7))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 60)) (q 4 (a (i (not (l (f (r (f (f 7)))))) (q 4 (c () (c () (c (c (f (f (f 7))) (f (r (r (f (f 7)))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (q 4 (c (f (f (r (f (f 7))))) (c (r (f (r (f (f 7))))) (c (c (f (f (f 7))) (f (r (r (f (f 7)))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ())))) 1) (c 4 ())) (q 2 (i (= 6 (q . 62)) (q 4 (a (i (not (l (f (r (r (f (f 7))))))) (q 4 (c () (c (c (f (f (f 7))) (f (r (f (f 7))))) (c () ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (q 4 (c (f (f (r (r (f (f 7)))))) (c (c (f (f (f 7))) (f (r (f (f 7))))) (c (r (f (r (r (f (f 7)))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ())))) 1) (c 4 ())) (q 2 (i (= 6 (q . 44)) (q 4 (c (c (substr (f (r (f 7))) () (q . 1)) (c (f (r (f (f 7)))) (c (f (r (r (f (f 7))))) ()))) (c (substr (f (r (f 7))) (q . 1)) (c (f (r (r (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 46)) (q 4 (c (f (f 7)) (c (f (r (f 7))) (c (concat (f (r (r (f 7)))) (f (f (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 91)) (q 2 (q 2 (q 4 (a -73 (c (c 39 (c 87 (c -73 -9))) (c (f 31) 4))) (c 6 ())) (c (c (substr 9 () 2) (substr 9 2)) 1)) (c (a 9 (c 9 (c (q . 1) 4))) 1)) (q 4 (f 7) (c 4 ()))) 1)) 1)) 1)) 1)) 1)) 1)) 1) (c (c (substr (f (r 3)) (q . 1)) (substr (f (r 3)) () (q . 1))) 1))))) ()))
   output: '"ABC"'
   runtime_cost: 478061
   byte_cost: 16872000
@@ -10,7 +10,7 @@ tests:
   - '"run(`+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.+.+.`, ``) = `ABC`"'
 - name: alphabet
   program: (a (q 5 (r (r (f (a 10 (c (c 8 (c 10 (c 22 30))) (c (c (c () (c () (c () ()))) (c () (c () ()))) (c (concat (q . 62) (a 12 (c 12 (c (q . 43) (q . 65)))) (q . 60) (a 12 (c 12 (c (q . 43) (q . 26)))) (q . "[->.+<]")) ())))))))) (c (c (c (q 2 (i 7 (q 2 (q 16 (a (i (= 6 (q . 91)) (q 2 5 (c 5 (c (+ 11 (q . 1)) 4))) (q 2 (i (= 6 (q . 93)) (q 2 (i (= 11 (q . 1)) (q) (q 2 5 (c 5 (c (- 11 (q . 1)) 4)))) 1) (q 2 5 (c 5 (c 11 4)))) 1)) 1) (q . 1)) (c (c (substr 7 (q . 1)) (substr 7 () (q . 1))) 1)) (q)) 1) (q 2 (i (> 7 ()) (q 14 5 (a 2 (c 2 (c 5 (- 7 (q . 1)))))) (q)) 1)) (c (q 2 (i 11 (q 2 10 (c (c 4 (c 10 (c 22 30))) (a 30 (c (c 4 (c 10 (c 22 30))) 3)))) (q . 3)) 1) (c (q 2 (i 17 (q 2 22 (c (c 4 (c 10 (c 22 30))) (c (f (a 10 (c (c 4 (c 10 (c 22 30))) (c 5 (c 7 ()))))) 7))) (q . 5)) 1) (q 2 (q 2 (i (= 6 (q . 43)) (q 4 (c (c (+ 35 (q . 1)) (c 83 (c -77 ()))) (c 43 (c 91 ()))) (c 4 ())) (q 2 (i (= 6 (q . 45)) (q 4 (c (c (- 35 (q . 1)) (c 83 (c -77 ()))) (c 43 (c 91 ()))) (c 4 ())) (q 2 (i (= 6 (q . 60)) (q 4 (a (i 83 (q 4 (c -109 (c -45 (c (c 35 -77) ()))) (c 43 (c 91 ()))) (q 4 (c () (c () (c (c 35 -77) ()))) (c 43 (c 91 ())))) 1) (c 4 ())) (q 2 (i (= 6 (q . 62)) (q 4 (a (i -77 (q 4 (c 307 (c (c 35 83) (c 435 ()))) (c 43 (c 91 ()))) (q 4 (c () (c (c 35 83) (c () ()))) (c 43 (c 91 ())))) 1) (c 4 ())) (q 2 (i (= 6 (q . 44)) (q 4 (c (c (substr 43 () (q . 1)) (c 83 (c -77 ()))) (c (substr 43 (q . 1)) (c 91 ()))) (c 4 ())) (q 2 (i (= 6 (q . 46)) (q 4 (c 19 (c 43 (c (concat 91 35) ()))) (c 4 ())) (q 2 (i (= 6 (q . 91)) (q 2 (q 4 (a 91 (c (c 19 (c 43 (c 91 123))) (c 23 (substr 9 () 2)))) (c (substr 9 2) ())) (c (a 9 (c 9 (c (q . 1) 4))) 1)) (q 4 11 (c 4 ()))) 1)) 1)) 1)) 1)) 1)) 1)) 1) (c (c (substr 11 (q . 1)) (substr 11 () (q . 1))) 1))))) ()))
-  debug_program: (a (q 2 (q 2 (q 2 (i ("debug_print" (q . "test:207:5") (concat (concat (concat (concat (concat (concat (q . "run(`") (concat (concat (concat (concat (q . 62) (a 51 (c 51 (c (q . 43) (q . 65))))) (q . 60)) (a 51 (c 51 (c (q . 43) (q . 26))))) (q . "[->.+<]"))) (q . "`, `")) ()) (q . "`) = `")) 2) (q . 96))) (q) (q . 2)) 1) (c (f (r (r (f (a 21 (c (c 17 (c 21 (c 45 61))) 2)))))) 1)) (c (c (c (c () (c () (c () ()))) (c () (c () ()))) (c (concat (concat (concat (concat (q . 62) (a 12 (c 12 (c (q . 43) (q . 65))))) (q . 60)) (a 12 (c 12 (c (q . 43) (q . 26))))) (q . "[->.+<]")) ())) 1)) (c (c (c (q 2 (i (= 7 ()) (q) (q 2 (q 16 (q . 1) (a (i (= 6 (q . 91)) (q 2 5 (c 5 (c (+ 11 (q . 1)) 4))) (q 2 (i (= 6 (q . 93)) (q 2 (i (= 11 (q . 1)) (q) (q 2 5 (c 5 (c (- 11 (q . 1)) 4)))) 1) (q 2 5 (c 5 (c 11 4)))) 1)) 1)) (c (c (substr 7 (q . 1)) (substr 7 () (q . 1))) 1))) 1) (q 2 (i (> 7 ()) (q 14 5 (a 2 (c 2 (c 5 (- 7 (q . 1)))))) (q)) 1)) (c (q 2 (i (= (f (r 3)) ()) (q . 3) (q 2 10 (c (c 4 (c 10 (c 22 30))) (a 30 (c (c 4 (c 10 (c 22 30))) 3))))) 1) (c (q 2 (i (= (f (f 5)) ()) (q . 5) (q 2 22 (c (c 4 (c 10 (c 22 30))) (c (f (a 10 (c (c 4 (c 10 (c 22 30))) (c 5 (c 7 ()))))) 7)))) 1) (q 2 (q 2 (i (= 6 (q . 43)) (q 4 (c (c (+ (f (f (f 7))) (q . 1)) (c (f (r (f (f 7)))) (c (f (r (r (f (f 7))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 45)) (q 4 (c (c (- (f (f (f 7))) (q . 1)) (c (f (r (f (f 7)))) (c (f (r (r (f (f 7))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 60)) (q 4 (a (i (not (l (f (r (f (f 7)))))) (q 4 (c () (c () (c (c (f (f (f 7))) (f (r (r (f (f 7)))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (q 4 (c (f (f (r (f (f 7))))) (c (r (f (r (f (f 7))))) (c (c (f (f (f 7))) (f (r (r (f (f 7)))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ())))) 1) (c 4 ())) (q 2 (i (= 6 (q . 62)) (q 4 (a (i (not (l (f (r (r (f (f 7))))))) (q 4 (c () (c (c (f (f (f 7))) (f (r (f (f 7))))) (c () ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (q 4 (c (f (f (r (r (f (f 7)))))) (c (c (f (f (f 7))) (f (r (f (f 7))))) (c (r (f (r (r (f (f 7)))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ())))) 1) (c 4 ())) (q 2 (i (= 6 (q . 44)) (q 4 (c (c (substr (f (r (f 7))) () (q . 1)) (c (f (r (f (f 7)))) (c (f (r (r (f (f 7))))) ()))) (c (substr (f (r (f 7))) (q . 1)) (c (f (r (r (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 46)) (q 4 (c (f (f 7)) (c (f (r (f 7))) (c (concat (f (r (r (f 7)))) (f (f (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 91)) (q 2 (q 2 (q 4 (a -73 (c (c 39 (c 87 (c -73 -9))) (c (f 31) 4))) (c 6 ())) (c (c (substr 9 () 2) (substr 9 2)) 1)) (c (a 9 (c 9 (c (q . 1) 4))) 1)) (q 4 (f 7) (c 4 ()))) 1)) 1)) 1)) 1)) 1)) 1)) 1) (c (c (substr (f (r 3)) (q . 1)) (substr (f (r 3)) () (q . 1))) 1))))) ()))
+  debug_program: (a (q 2 (q 2 (q 2 (i ("debug_print" (q . "brainfck.rue:207:5") (concat (concat (concat (concat (concat (concat (q . "run(`") (concat (concat (concat (concat (q . 62) (a 51 (c 51 (c (q . 43) (q . 65))))) (q . 60)) (a 51 (c 51 (c (q . 43) (q . 26))))) (q . "[->.+<]"))) (q . "`, `")) ()) (q . "`) = `")) 2) (q . 96))) (q) (q . 2)) 1) (c (f (r (r (f (a 21 (c (c 17 (c 21 (c 45 61))) 2)))))) 1)) (c (c (c (c () (c () (c () ()))) (c () (c () ()))) (c (concat (concat (concat (concat (q . 62) (a 12 (c 12 (c (q . 43) (q . 65))))) (q . 60)) (a 12 (c 12 (c (q . 43) (q . 26))))) (q . "[->.+<]")) ())) 1)) (c (c (c (q 2 (i (= 7 ()) (q) (q 2 (q 16 (q . 1) (a (i (= 6 (q . 91)) (q 2 5 (c 5 (c (+ 11 (q . 1)) 4))) (q 2 (i (= 6 (q . 93)) (q 2 (i (= 11 (q . 1)) (q) (q 2 5 (c 5 (c (- 11 (q . 1)) 4)))) 1) (q 2 5 (c 5 (c 11 4)))) 1)) 1)) (c (c (substr 7 (q . 1)) (substr 7 () (q . 1))) 1))) 1) (q 2 (i (> 7 ()) (q 14 5 (a 2 (c 2 (c 5 (- 7 (q . 1)))))) (q)) 1)) (c (q 2 (i (= (f (r 3)) ()) (q . 3) (q 2 10 (c (c 4 (c 10 (c 22 30))) (a 30 (c (c 4 (c 10 (c 22 30))) 3))))) 1) (c (q 2 (i (= (f (f 5)) ()) (q . 5) (q 2 22 (c (c 4 (c 10 (c 22 30))) (c (f (a 10 (c (c 4 (c 10 (c 22 30))) (c 5 (c 7 ()))))) 7)))) 1) (q 2 (q 2 (i (= 6 (q . 43)) (q 4 (c (c (+ (f (f (f 7))) (q . 1)) (c (f (r (f (f 7)))) (c (f (r (r (f (f 7))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 45)) (q 4 (c (c (- (f (f (f 7))) (q . 1)) (c (f (r (f (f 7)))) (c (f (r (r (f (f 7))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 60)) (q 4 (a (i (not (l (f (r (f (f 7)))))) (q 4 (c () (c () (c (c (f (f (f 7))) (f (r (r (f (f 7)))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (q 4 (c (f (f (r (f (f 7))))) (c (r (f (r (f (f 7))))) (c (c (f (f (f 7))) (f (r (r (f (f 7)))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ())))) 1) (c 4 ())) (q 2 (i (= 6 (q . 62)) (q 4 (a (i (not (l (f (r (r (f (f 7))))))) (q 4 (c () (c (c (f (f (f 7))) (f (r (f (f 7))))) (c () ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ()))) (q 4 (c (f (f (r (r (f (f 7)))))) (c (c (f (f (f 7))) (f (r (f (f 7))))) (c (r (f (r (r (f (f 7)))))) ()))) (c (f (r (f 7))) (c (f (r (r (f 7)))) ())))) 1) (c 4 ())) (q 2 (i (= 6 (q . 44)) (q 4 (c (c (substr (f (r (f 7))) () (q . 1)) (c (f (r (f (f 7)))) (c (f (r (r (f (f 7))))) ()))) (c (substr (f (r (f 7))) (q . 1)) (c (f (r (r (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 46)) (q 4 (c (f (f 7)) (c (f (r (f 7))) (c (concat (f (r (r (f 7)))) (f (f (f 7)))) ()))) (c 4 ())) (q 2 (i (= 6 (q . 91)) (q 2 (q 2 (q 4 (a -73 (c (c 39 (c 87 (c -73 -9))) (c (f 31) 4))) (c 6 ())) (c (c (substr 9 () 2) (substr 9 2)) 1)) (c (a 9 (c 9 (c (q . 1) 4))) 1)) (q 4 (f 7) (c 4 ()))) 1)) 1)) 1)) 1)) 1)) 1)) 1) (c (c (substr (f (r 3)) (q . 1)) (substr (f (r 3)) () (q . 1))) 1))))) ()))
   output: '"ABCDEFGHIJKLMNOPQRSTUVWXYZ"'
   runtime_cost: 1454359
   byte_cost: 17280000
diff --git a/tests/blocks/improper_blocks.yaml b/tests/blocks/improper_blocks.yaml
index ace19a2e..70f97378 100644
--- a/tests/blocks/improper_blocks.yaml
+++ b/tests/blocks/improper_blocks.yaml
@@ -1,11 +1,11 @@
 diagnostics:
-- Block does not return a value at test:3:36
-- Cannot assign `nil` to `Int` without a cast, since they are semantically different at test:3:36
-- Condition always evaluates to `true` at test:6:8
-- Block does not return a value at test:6:13
-- Condition always evaluates to `true` at test:10:8
-- Expected statement block to end in `return` or `raise`, not an expression at test:11:9
-- Cannot use a `return` statement here, end the block with an expression instead at test:16:5
-- Condition always evaluates to `true` at test:20:8
-- Cannot use a `return` statement here, end the block with an expression instead at test:21:9
-- Cannot use a `return` statement here, end the block with an expression instead at test:23:9
+- Block does not return a value at improper_blocks.rue:3:36
+- Cannot assign `nil` to `Int` without a cast, since they are semantically different at improper_blocks.rue:3:36
+- Condition always evaluates to `true` at improper_blocks.rue:6:8
+- Block does not return a value at improper_blocks.rue:6:13
+- Condition always evaluates to `true` at improper_blocks.rue:10:8
+- Expected statement block to end in `return` or `raise`, not an expression at improper_blocks.rue:11:9
+- Cannot use a `return` statement here, end the block with an expression instead at improper_blocks.rue:16:5
+- Condition always evaluates to `true` at improper_blocks.rue:20:8
+- Cannot use a `return` statement here, end the block with an expression instead at improper_blocks.rue:21:9
+- Cannot use a `return` statement here, end the block with an expression instead at improper_blocks.rue:23:9
diff --git a/tests/blocks/let_missing_value.yaml b/tests/blocks/let_missing_value.yaml
index 1757b97e..1c9c8b58 100644
--- a/tests/blocks/let_missing_value.yaml
+++ b/tests/blocks/let_missing_value.yaml
@@ -1,5 +1,5 @@
 diagnostics:
-- Let bindings must have a value, since they cannot be reassigned at test:2:5
-- Let bindings must have a value, since they cannot be reassigned at test:3:5
-- Unused binding `missing` at test:2:9
-- Unused binding `with_type` at test:3:9
+- Let bindings must have a value, since they cannot be reassigned at let_missing_value.rue:2:5
+- Let bindings must have a value, since they cannot be reassigned at let_missing_value.rue:3:5
+- Unused binding `missing` at let_missing_value.rue:2:9
+- Unused binding `with_type` at let_missing_value.rue:3:9
diff --git a/tests/blocks/missing_return_type.yaml b/tests/blocks/missing_return_type.yaml
index f28a84d0..323e603f 100644
--- a/tests/blocks/missing_return_type.yaml
+++ b/tests/blocks/missing_return_type.yaml
@@ -1,2 +1,2 @@
 diagnostics:
-- Cannot assign `42` to `nil`, since they are incompatible at test:7:22
+- Cannot assign `42` to `nil`, since they are incompatible at missing_return_type.rue:7:22
diff --git a/tests/debug/print.yaml b/tests/debug/print.yaml
index 3bb95032..f6764135 100644
--- a/tests/debug/print.yaml
+++ b/tests/debug/print.yaml
@@ -1,7 +1,7 @@
 tests:
 - name: single_print
   program: ()
-  debug_program: (a (i ("debug_print" (q . "test:2:5") (q . "Hello, world!")) (q) (q)) 1)
+  debug_program: (a (i ("debug_print" (q . "print.rue:2:5") (q . "Hello, world!")) (q) (q)) 1)
   output: ()
   runtime_cost: 44
   byte_cost: 12000
@@ -10,7 +10,7 @@ tests:
   - '"Hello, world!"'
 - name: multiple_prints
   program: ()
-  debug_program: (a (i ("debug_print" (q . "test:6:5") (q . 1)) (q) (q 2 (i ("debug_print" (q . "test:7:5") (q . 2)) (q) (q 2 (i ("debug_print" (q . "test:8:5") (q . 3)) (q) (q)) 1)) 1)) 1)
+  debug_program: (a (i ("debug_print" (q . "print.rue:6:5") (q . 1)) (q) (q 2 (i ("debug_print" (q . "print.rue:7:5") (q . 2)) (q) (q 2 (i ("debug_print" (q . "print.rue:8:5") (q . 3)) (q) (q)) 1)) 1)) 1)
   output: ()
   runtime_cost: 44
   byte_cost: 12000
@@ -21,7 +21,7 @@ tests:
   - '3'
 - name: print_recursive
   program: (a (q 2 2 (c 2 (c (q . 1) (c (q . 2) (c (q . 3) ()))))) (c (q 2 (i 3 (q 2 2 (c 2 7)) (q)) 1) ()))
-  debug_program: (a (q 3 (q . 1) () (a 2 (c 2 (c (q . 1) (c (q . 2) (c (q . 3) ())))))) (c (q 2 (i (not (l 3)) (q) (q 2 (i ("debug_print" (q . "test:20:5") (f 3)) (q) (q 3 (q . 1) () (a 2 (c 2 (r 3))))) 1)) 1) ()))
+  debug_program: (a (q 3 (q . 1) () (a 2 (c 2 (c (q . 1) (c (q . 2) (c (q . 3) ())))))) (c (q 2 (i (not (l 3)) (q) (q 2 (i ("debug_print" (q . "print.rue:20:5") (f 3)) (q) (q 3 (q . 1) () (a 2 (c 2 (r 3))))) 1)) 1) ()))
   output: ()
   runtime_cost: 2663
   byte_cost: 996000
@@ -32,7 +32,7 @@ tests:
   - '3'
 - name: print_with_assertions
   program: (a (q 3 (a 2 (c (q . "hello") ())) (a 2 (c (q . "goodbye") ())) (a 2 (c (q . "hello") (q . "world")))) (c (q 2 (i (l 1) (q 2 (i (l 2) (q 8) (q 2 (i (a (i (l 3) (q) (q 2 (i 3 (q) (q 1 . 1)) 1)) 1) (q) (q 8)) 1)) 1) (q 8)) 1) ()))
-  debug_program: (a (q 2 (i ("debug_print" (q . "test:26:5") (q . "First test")) (q) (q 3 (q . 1) (a (i ("debug_print" (q . "test:28:5") (q . "Second test")) (q) (q 3 (q . 1) (a (i ("debug_print" (q . "test:30:5") (q . "Third test")) (q) (q 3 (q . 1) () (a 2 (c (q . "hello") (q . "world"))))) 1) (a 2 (c (q . "goodbye") ())))) 1) (a 2 (c (q . "hello") ())))) 1) (c (q 2 (i ("debug_print" (q . "test:35:5") (q . "Asserting value is a pair")) (q) (q 2 (i (l 1) (q 2 (i ("debug_print" (q . "test:37:5") (q . "Asserting first is a string")) (q) (q 2 (i (not (l (f 1))) (q 2 (i ("debug_print" (q . "test:39:5") (q . "Asserting rest is nil")) (q) (q 2 (i ("debug_print" (q . "test:40:5") 1) (q) (q 2 (i (a (i (not (l (r 1))) (q 2 (i (= (r 1) ()) (q 1 . 1) (q)) 1) (q)) 1) (q 2 (i ("debug_print" (q . "test:42:5") (q . "Value is valid")) (q) (q)) 1) (q 8 (q . "assertion failed at 41:5"))) 1)) 1)) 1) (q 8 (q . "assertion failed at 38:5"))) 1)) 1) (q 8 (q . "assertion failed at 36:5"))) 1)) 1) ()))
+  debug_program: (a (q 2 (i ("debug_print" (q . "print.rue:26:5") (q . "First test")) (q) (q 3 (q . 1) (a (i ("debug_print" (q . "print.rue:28:5") (q . "Second test")) (q) (q 3 (q . 1) (a (i ("debug_print" (q . "print.rue:30:5") (q . "Third test")) (q) (q 3 (q . 1) () (a 2 (c (q . "hello") (q . "world"))))) 1) (a 2 (c (q . "goodbye") ())))) 1) (a 2 (c (q . "hello") ())))) 1) (c (q 2 (i ("debug_print" (q . "print.rue:35:5") (q . "Asserting value is a pair")) (q) (q 2 (i (l 1) (q 2 (i ("debug_print" (q . "print.rue:37:5") (q . "Asserting first is a string")) (q) (q 2 (i (not (l (f 1))) (q 2 (i ("debug_print" (q . "print.rue:39:5") (q . "Asserting rest is nil")) (q) (q 2 (i ("debug_print" (q . "print.rue:40:5") 1) (q) (q 2 (i (a (i (not (l (r 1))) (q 2 (i (= (r 1) ()) (q 1 . 1) (q)) 1) (q)) 1) (q 2 (i ("debug_print" (q . "print.rue:42:5") (q . "Value is valid")) (q) (q)) 1) (q 8 (q . "assertion failed at 41:5"))) 1)) 1)) 1) (q 8 (q . "assertion failed at 38:5"))) 1)) 1) (q 8 (q . "assertion failed at 36:5"))) 1)) 1) ()))
   byte_cost: 2412000
   clvm_error: clvm raise ()
   debug_clvm_error: clvm raise "assertion failed at 41:5"
diff --git a/tests/guards/impossible_checks.yaml b/tests/guards/impossible_checks.yaml
index 8bea4496..bcb49ac1 100644
--- a/tests/guards/impossible_checks.yaml
+++ b/tests/guards/impossible_checks.yaml
@@ -1,4 +1,4 @@
 diagnostics:
-- Cannot check if value is of function type at runtime at test:2:5
-- Recursion depth exceeded while checking type at test:6:5
-- Recursion depth exceeded while checking type at test:10:5
+- Cannot check if value is of function type at runtime at impossible_checks.rue:2:5
+- Recursion depth exceeded while checking type at impossible_checks.rue:6:5
+- Recursion depth exceeded while checking type at impossible_checks.rue:10:5
diff --git a/tests/imports/duplicate_imports.yaml b/tests/imports/duplicate_imports.yaml
index 69232cb0..9e91f18d 100644
--- a/tests/imports/duplicate_imports.yaml
+++ b/tests/imports/duplicate_imports.yaml
@@ -5,5 +5,5 @@ runtime_cost: 20
 byte_cost: 36000
 total_cost: 36020
 diagnostics:
-- Unused import `thing` at test:6:12
-- Unused import `thing` at test:7:12
+- Unused import `thing` at duplicate_imports.rue:6:12
+- Unused import `thing` at duplicate_imports.rue:7:12
diff --git a/tests/imports/unresolved_imports.yaml b/tests/imports/unresolved_imports.yaml
index 746c8883..ba33c32e 100644
--- a/tests/imports/unresolved_imports.yaml
+++ b/tests/imports/unresolved_imports.yaml
@@ -1,4 +1,4 @@
 diagnostics:
-- Undeclared symbol `inner` at test:4:16
-- Undeclared symbol `inner` at test:5:16
-- Unresolved import `missing` at test:3:16
+- Undeclared symbol `inner` at unresolved_imports.rue:4:16
+- Undeclared symbol `inner` at unresolved_imports.rue:5:16
+- Unresolved import `missing` at unresolved_imports.rue:3:16
diff --git a/tests/operators.yaml b/tests/operators.yaml
index 6f052741..26477f09 100644
--- a/tests/operators.yaml
+++ b/tests/operators.yaml
@@ -21,6 +21,6 @@ tests:
   byte_cost: 2628000
   total_cost: 2633714
 diagnostics:
-- Unnecessary `+` operator, since it has no effect at test:2:12
-- Condition always evaluates to `true` at test:51:12
-- Condition always evaluates to `true` at test:52:12
+- Unnecessary `+` operator, since it has no effect at operators.rue:2:12
+- Condition always evaluates to `true` at operators.rue:51:12
+- Condition always evaluates to `true` at operators.rue:52:12
diff --git a/tests/projects/multi_file.yaml b/tests/projects/multi_file.yaml
new file mode 100644
index 00000000..ab00ec1f
--- /dev/null
+++ b/tests/projects/multi_file.yaml
@@ -0,0 +1,15 @@
+tests:
+- name: greet_world
+  program: (q . "Hello, world!")
+  debug_program: (a (q 2 2 (q . "world")) (c (q 14 (concat (q . "Hello, ") 1) (q . 33)) ()))
+  output: '"Hello, world!"'
+  runtime_cost: 20
+  byte_cost: 192000
+  total_cost: 192020
+- name: greet_alice
+  program: (q . "Hello, Alice!")
+  debug_program: (a (q 2 2 (q . "Alice")) (c (q 14 (concat (q . "Hello, ") 1) (q . 33)) ()))
+  output: '"Hello, Alice!"'
+  runtime_cost: 20
+  byte_cost: 192000
+  total_cost: 192020
diff --git a/tests/projects/multi_file/main.rue b/tests/projects/multi_file/main.rue
new file mode 100644
index 00000000..ee2f67f2
--- /dev/null
+++ b/tests/projects/multi_file/main.rue
@@ -0,0 +1,9 @@
+import utils::greet;
+
+test fn greet_world() -> String {
+    greet("world")
+}
+
+test fn greet_alice() -> String {
+    greet("Alice")
+}
diff --git a/tests/projects/multi_file/utils.rue b/tests/projects/multi_file/utils.rue
new file mode 100644
index 00000000..a8680619
--- /dev/null
+++ b/tests/projects/multi_file/utils.rue
@@ -0,0 +1,3 @@
+export fn greet(name: String) -> String {
+    "Hello, " + name + "!"
+}
diff --git a/tests/projects/single_file.yaml b/tests/projects/single_file.yaml
new file mode 100644
index 00000000..12d9ead6
--- /dev/null
+++ b/tests/projects/single_file.yaml
@@ -0,0 +1,6 @@
+program: (q . "Hello, world!")
+debug_program: (q . "Hello, world!")
+output: '"Hello, world!"'
+runtime_cost: 20
+byte_cost: 192000
+total_cost: 192020
diff --git a/tests/projects/single_file/main.rue b/tests/projects/single_file/main.rue
new file mode 100644
index 00000000..65f92b1f
--- /dev/null
+++ b/tests/projects/single_file/main.rue
@@ -0,0 +1,3 @@
+fn main() -> String {
+    "Hello, world!"
+}
diff --git a/tests/projects/subdirectory.yaml b/tests/projects/subdirectory.yaml
new file mode 100644
index 00000000..b191010a
--- /dev/null
+++ b/tests/projects/subdirectory.yaml
@@ -0,0 +1,6 @@
+program: (q . "inner outer")
+debug_program: (a (q 2 4 (c 6 ())) (c (c (q 14 (q . "inner ") (a 2 ())) (q 1 . "outer")) ()))
+output: '"inner outer"'
+runtime_cost: 20
+byte_cost: 168000
+total_cost: 168020
diff --git a/tests/projects/subdirectory/a/b/c/inner.rue b/tests/projects/subdirectory/a/b/c/inner.rue
new file mode 100644
index 00000000..200de6ea
--- /dev/null
+++ b/tests/projects/subdirectory/a/b/c/inner.rue
@@ -0,0 +1,3 @@
+export fn inner() -> String {
+    "inner " + super::super::super::main::outer()
+}
diff --git a/tests/projects/subdirectory/main.rue b/tests/projects/subdirectory/main.rue
new file mode 100644
index 00000000..bdfed422
--- /dev/null
+++ b/tests/projects/subdirectory/main.rue
@@ -0,0 +1,7 @@
+fn main() -> String {
+    a::b::c::inner::inner()
+}
+
+export fn outer() -> String {
+    "outer"
+}
diff --git a/tests/symbols/expr_statements.yaml b/tests/symbols/expr_statements.yaml
index 415d23a4..98d0fe1b 100644
--- a/tests/symbols/expr_statements.yaml
+++ b/tests/symbols/expr_statements.yaml
@@ -64,9 +64,9 @@ tests:
   byte_cost: 852000
   total_cost: 854884
 diagnostics:
-- Value returned by statement is unused at test:22:5
-- Value returned by statement is unused at test:27:5
-- Value returned by statement is unused at test:31:5
-- Value returned by statement is unused at test:32:5
-- Value returned by statement is unused at test:36:5
-- Value returned by statement is unused at test:37:5
+- Value returned by statement is unused at expr_statements.rue:22:5
+- Value returned by statement is unused at expr_statements.rue:27:5
+- Value returned by statement is unused at expr_statements.rue:31:5
+- Value returned by statement is unused at expr_statements.rue:32:5
+- Value returned by statement is unused at expr_statements.rue:36:5
+- Value returned by statement is unused at expr_statements.rue:37:5
diff --git a/tests/symbols/function_arguments.yaml b/tests/symbols/function_arguments.yaml
index 3e64e183..270539e6 100644
--- a/tests/symbols/function_arguments.yaml
+++ b/tests/symbols/function_arguments.yaml
@@ -1,14 +1,14 @@
 diagnostics:
-- Expected 2 arguments, but found 0 at test:6:5
-- Expected 2 arguments, but found 1 at test:7:5
-- Expected 2 arguments, but found 3 at test:8:5
-- Spread operator must be used on functions with spread parameters at test:12:5
-- Expected 2 arguments, but found 1 at test:20:5
-- Expected 2 arguments, but found 3 at test:21:5
-- Spread operator must be used on functions with spread parameters at test:25:5
-- Expected 2 arguments, but found 0 at test:25:5
-- Spread operator must be used on functions with spread parameters at test:26:5
-- Expected 2 arguments, but found 1 at test:26:5
-- Spread operator must be used on functions with spread parameters at test:27:5
-- Spread operator must be used on functions with spread parameters at test:28:5
-- Expected 2 arguments, but found 3 at test:28:5
+- Expected 2 arguments, but found 0 at function_arguments.rue:6:5
+- Expected 2 arguments, but found 1 at function_arguments.rue:7:5
+- Expected 2 arguments, but found 3 at function_arguments.rue:8:5
+- Spread operator must be used on functions with spread parameters at function_arguments.rue:12:5
+- Expected 2 arguments, but found 1 at function_arguments.rue:20:5
+- Expected 2 arguments, but found 3 at function_arguments.rue:21:5
+- Spread operator must be used on functions with spread parameters at function_arguments.rue:25:5
+- Expected 2 arguments, but found 0 at function_arguments.rue:25:5
+- Spread operator must be used on functions with spread parameters at function_arguments.rue:26:5
+- Expected 2 arguments, but found 1 at function_arguments.rue:26:5
+- Spread operator must be used on functions with spread parameters at function_arguments.rue:27:5
+- Spread operator must be used on functions with spread parameters at function_arguments.rue:28:5
+- Expected 2 arguments, but found 3 at function_arguments.rue:28:5
diff --git a/tests/symbols/invalid_recursion.yaml b/tests/symbols/invalid_recursion.yaml
index aced3740..b486c56a 100644
--- a/tests/symbols/invalid_recursion.yaml
+++ b/tests/symbols/invalid_recursion.yaml
@@ -1,6 +1,6 @@
 diagnostics:
-- Function `factorial` cannot be inline, since it references itself at test:5:11
-- Constant `A` references itself at test:13:7
-- Constant `B` references itself at test:14:7
-- Constant `C` references itself at test:15:7
-- Constant `D` references itself at test:16:14
+- Function `factorial` cannot be inline, since it references itself at invalid_recursion.rue:5:11
+- Constant `A` references itself at invalid_recursion.rue:13:7
+- Constant `B` references itself at invalid_recursion.rue:14:7
+- Constant `C` references itself at invalid_recursion.rue:15:7
+- Constant `D` references itself at invalid_recursion.rue:16:14
diff --git a/tests/symbols/private_reference.yaml b/tests/symbols/private_reference.yaml
index c08d684a..3eebf567 100644
--- a/tests/symbols/private_reference.yaml
+++ b/tests/symbols/private_reference.yaml
@@ -1,4 +1,4 @@
 diagnostics:
-- Cannot reference private type `Type` in module `private` at test:9:23
-- Cannot reference private symbol `function` in module `private` at test:10:14
-- Block does not return a value at test:9:28
+- Cannot reference private type `Type` in module `private` at private_reference.rue:9:23
+- Cannot reference private symbol `function` in module `private` at private_reference.rue:10:14
+- Block does not return a value at private_reference.rue:9:28
diff --git a/tests/symbols/super_errors.yaml b/tests/symbols/super_errors.yaml
index 51362c40..dd676561 100644
--- a/tests/symbols/super_errors.yaml
+++ b/tests/symbols/super_errors.yaml
@@ -1,10 +1,10 @@
 diagnostics:
-- Unresolved `super`, there is no parent module at test:2:12
-- Unresolved `super`, there is no parent module at test:5:8
-- Cannot end path in `super` at test:6:8
-- Unresolved `super`, there is no parent module at test:7:8
-- Cannot end path in `super` at test:7:15
-- Unresolved import `x` at test:5:15
-- Unresolved import `super` at test:6:8
-- Unresolved import `super` at test:7:15
-- Unused import `a` at test:2:19
+- Unresolved `super`, there is no parent module at super_errors.rue:2:12
+- Unresolved `super`, there is no parent module at super_errors.rue:5:8
+- Cannot end path in `super` at super_errors.rue:6:8
+- Unresolved `super`, there is no parent module at super_errors.rue:7:8
+- Cannot end path in `super` at super_errors.rue:7:15
+- Unresolved import `x` at super_errors.rue:5:15
+- Unresolved import `super` at super_errors.rue:6:8
+- Unresolved import `super` at super_errors.rue:7:15
+- Unused import `a` at super_errors.rue:2:19
diff --git a/tests/symbols/tree_shaking.yaml b/tests/symbols/tree_shaking.yaml
index 44f08a70..e6a489ac 100644
--- a/tests/symbols/tree_shaking.yaml
+++ b/tests/symbols/tree_shaking.yaml
@@ -13,5 +13,5 @@ tests:
   byte_cost: 444000
   total_cost: 445642
 diagnostics:
-- Unused binding `a` at test:2:9
-- Unused binding `b` at test:3:9
+- Unused binding `a` at tree_shaking.rue:2:9
+- Unused binding `b` at tree_shaking.rue:3:9
diff --git a/tests/types/literal_errors.yaml b/tests/types/literal_errors.yaml
index 82a8258d..5046fded 100644
--- a/tests/types/literal_errors.yaml
+++ b/tests/types/literal_errors.yaml
@@ -1,6 +1,6 @@
 diagnostics:
-- Cannot assign `34` to `42`, since they are incompatible at test:1:27
-- Cannot assign `0xcafe` to `0xcafef00d`, since they are incompatible at test:5:38
-- Cannot assign `"Hello!"` to `"Hello, world!"`, since they are incompatible at test:9:43
-- Cannot assign `false` to `true`, since they are incompatible at test:13:30
-- Cannot assign `nil` to `true`, since they are incompatible at test:17:29
+- Cannot assign `34` to `42`, since they are incompatible at literal_errors.rue:1:27
+- Cannot assign `0xcafe` to `0xcafef00d`, since they are incompatible at literal_errors.rue:5:38
+- Cannot assign `"Hello!"` to `"Hello, world!"`, since they are incompatible at literal_errors.rue:9:43
+- Cannot assign `false` to `true`, since they are incompatible at literal_errors.rue:13:30
+- Cannot assign `nil` to `true`, since they are incompatible at literal_errors.rue:17:29
diff --git a/tests/types/struct_error.yaml b/tests/types/struct_error.yaml
index 803d7d1c..2638c7a8 100644
--- a/tests/types/struct_error.yaml
+++ b/tests/types/struct_error.yaml
@@ -1,2 +1,2 @@
 diagnostics:
-- Cannot assign `"1"` to `Int` without a cast, since they are semantically different at test:8:9
+- Cannot assign `"1"` to `Int` without a cast, since they are semantically different at struct_error.rue:8:9
diff --git a/tests/warnings/always_condition.yaml b/tests/warnings/always_condition.yaml
index 60fbefa3..4b9ea672 100644
--- a/tests/warnings/always_condition.yaml
+++ b/tests/warnings/always_condition.yaml
@@ -5,6 +5,6 @@ runtime_cost: 20
 byte_cost: 36000
 total_cost: 36020
 diagnostics:
-- Condition always evaluates to `true` at test:2:12
-- Condition always evaluates to `true` at test:3:12
-- Condition always evaluates to `false` at test:5:8
+- Condition always evaluates to `true` at always_condition.rue:2:12
+- Condition always evaluates to `true` at always_condition.rue:3:12
+- Condition always evaluates to `false` at always_condition.rue:5:8
diff --git a/tests/warnings/empty_generic_parameters.yaml b/tests/warnings/empty_generic_parameters.yaml
index 1e605ff5..3a2925bf 100644
--- a/tests/warnings/empty_generic_parameters.yaml
+++ b/tests/warnings/empty_generic_parameters.yaml
@@ -5,8 +5,8 @@ runtime_cost: 44
 byte_cost: 12000
 total_cost: 12044
 diagnostics:
-- Unnecessary empty generic parameter list specified at test:6:14
-- Unnecessary empty generic parameter list specified at test:8:11
-- Unnecessary empty generic argument list specified at test:1:19
-- Unnecessary empty generic parameter list specified at test:10:12
-- Unnecessary empty generic argument list specified at test:8:22
+- Unnecessary empty generic parameter list specified at empty_generic_parameters.rue:6:14
+- Unnecessary empty generic parameter list specified at empty_generic_parameters.rue:8:11
+- Unnecessary empty generic argument list specified at empty_generic_parameters.rue:1:19
+- Unnecessary empty generic parameter list specified at empty_generic_parameters.rue:10:12
+- Unnecessary empty generic argument list specified at empty_generic_parameters.rue:8:22
diff --git a/tests/warnings/unnecessary_cast.yaml b/tests/warnings/unnecessary_cast.yaml
index c120e172..1bfff766 100644
--- a/tests/warnings/unnecessary_cast.yaml
+++ b/tests/warnings/unnecessary_cast.yaml
@@ -49,7 +49,7 @@ tests:
   byte_cost: 156000
   total_cost: 156146
 diagnostics:
-- Unnecessary cast from `42` to `42`, since they are compatible with each other at test:2:5
-- Unnecessary cast from `A` to `A`, since they are compatible with each other at test:14:5
-- Unnecessary cast from `A` to `Alias`, since they are compatible with each other at test:22:5
-- Unnecessary cast from `Alias` to `A`, since they are compatible with each other at test:26:5
+- Unnecessary cast from `42` to `42`, since they are compatible with each other at unnecessary_cast.rue:2:5
+- Unnecessary cast from `A` to `A`, since they are compatible with each other at unnecessary_cast.rue:14:5
+- Unnecessary cast from `A` to `Alias`, since they are compatible with each other at unnecessary_cast.rue:22:5
+- Unnecessary cast from `Alias` to `A`, since they are compatible with each other at unnecessary_cast.rue:26:5
diff --git a/tests/warnings/unnecessary_guard.yaml b/tests/warnings/unnecessary_guard.yaml
index e49c44d3..beea91d0 100644
--- a/tests/warnings/unnecessary_guard.yaml
+++ b/tests/warnings/unnecessary_guard.yaml
@@ -49,11 +49,11 @@ tests:
   byte_cost: 36000
   total_cost: 36020
 diagnostics:
-- Unnecessary type guard from `Int` to `Int`, since they are already compatible types at test:2:5
-- Unnecessary type guard from `42` to `Int`, since they are already compatible types at test:6:5
-- Unnecessary type guard from `A` to `A`, since they are already compatible types at test:14:5
-- Unnecessary cast from `A` to `Alias`, since they are compatible with each other at test:22:5
-- Unnecessary type guard from `Alias` to `A`, since they are already compatible types at test:22:5
-- Unnecessary cast from `Alias` to `A`, since they are compatible with each other at test:26:5
-- Unnecessary type guard from `A` to `A`, since they are already compatible types at test:26:5
-- Unused struct `B` at test:33:8
+- Unnecessary type guard from `Int` to `Int`, since they are already compatible types at unnecessary_guard.rue:2:5
+- Unnecessary type guard from `42` to `Int`, since they are already compatible types at unnecessary_guard.rue:6:5
+- Unnecessary type guard from `A` to `A`, since they are already compatible types at unnecessary_guard.rue:14:5
+- Unnecessary cast from `A` to `Alias`, since they are compatible with each other at unnecessary_guard.rue:22:5
+- Unnecessary type guard from `Alias` to `A`, since they are already compatible types at unnecessary_guard.rue:22:5
+- Unnecessary cast from `Alias` to `A`, since they are compatible with each other at unnecessary_guard.rue:26:5
+- Unnecessary type guard from `A` to `A`, since they are already compatible types at unnecessary_guard.rue:26:5
+- Unused struct `B` at unnecessary_guard.rue:33:8
diff --git a/tests/warnings/unnecessary_plus.yaml b/tests/warnings/unnecessary_plus.yaml
index 2456ef89..c7108da8 100644
--- a/tests/warnings/unnecessary_plus.yaml
+++ b/tests/warnings/unnecessary_plus.yaml
@@ -5,4 +5,4 @@ runtime_cost: 20
 byte_cost: 36000
 total_cost: 36020
 diagnostics:
-- Unnecessary `+` operator, since it has no effect at test:2:5
+- Unnecessary `+` operator, since it has no effect at unnecessary_plus.rue:2:5
diff --git a/tests/warnings/unused_children.yaml b/tests/warnings/unused_children.yaml
index 72b3c461..6f87c4f2 100644
--- a/tests/warnings/unused_children.yaml
+++ b/tests/warnings/unused_children.yaml
@@ -1,10 +1,10 @@
 diagnostics:
-- Unused function `unused_parameter` at test:1:4
-- Unused parameter `value` at test:1:21
-- Unused function `used_parameter` at test:3:4
-- Unused function `unused_generic` at test:7:4
-- Unused function `used_generic` at test:9:4
-- Unused function `unused_binding` at test:13:4
-- Unused function `used_binding` at test:17:4
-- Unused binding `x` at test:14:9
-- Unused generic type `T` at test:7:19
+- Unused function `unused_parameter` at unused_children.rue:1:4
+- Unused parameter `value` at unused_children.rue:1:21
+- Unused function `used_parameter` at unused_children.rue:3:4
+- Unused function `unused_generic` at unused_children.rue:7:4
+- Unused function `used_generic` at unused_children.rue:9:4
+- Unused function `unused_binding` at unused_children.rue:13:4
+- Unused function `used_binding` at unused_children.rue:17:4
+- Unused binding `x` at unused_children.rue:14:9
+- Unused generic type `T` at unused_children.rue:7:19
diff --git a/tests/warnings/unused_imports.yaml b/tests/warnings/unused_imports.yaml
index 886502c1..ce9c1be7 100644
--- a/tests/warnings/unused_imports.yaml
+++ b/tests/warnings/unused_imports.yaml
@@ -5,16 +5,16 @@ runtime_cost: 20
 byte_cost: 36000
 total_cost: 36020
 diagnostics:
-- Unused import `d` at test:38:18
-- Unused import `*` at test:36:18
-- Unused import `*` at test:39:17
-- Unused import `*` at test:40:15
-- Unused import `a` at test:33:16
-- Unused import `*` at test:34:14
-- Unused import `c` at test:35:18
-- Unused import `*` at test:37:18
-- Unused function `a` at test:2:15
-- Unused function `b` at test:8:15
-- Unused function `c` at test:14:15
-- Unused function `d` at test:20:15
-- Unused function `private` at test:26:8
+- Unused import `d` at unused_imports.rue:38:18
+- Unused import `*` at unused_imports.rue:36:18
+- Unused import `*` at unused_imports.rue:39:17
+- Unused import `*` at unused_imports.rue:40:15
+- Unused import `a` at unused_imports.rue:33:16
+- Unused import `*` at unused_imports.rue:34:14
+- Unused import `c` at unused_imports.rue:35:18
+- Unused import `*` at unused_imports.rue:37:18
+- Unused function `a` at unused_imports.rue:2:15
+- Unused function `b` at unused_imports.rue:8:15
+- Unused function `c` at unused_imports.rue:14:15
+- Unused function `d` at unused_imports.rue:20:15
+- Unused function `private` at unused_imports.rue:26:8
diff --git a/tests/warnings/unused_parameters.yaml b/tests/warnings/unused_parameters.yaml
index fa96b3fd..722fc088 100644
--- a/tests/warnings/unused_parameters.yaml
+++ b/tests/warnings/unused_parameters.yaml
@@ -43,7 +43,7 @@ tests:
   byte_cost: 12000
   total_cost: 12048
 diagnostics:
-- Unused parameter `value` at test:1:31
-- Unused parameter `value` at test:21:21
-- Unused generic type `T` at test:3:29
-- Unused generic type `T` at test:27:19
+- Unused parameter `value` at unused_parameters.rue:1:31
+- Unused parameter `value` at unused_parameters.rue:21:21
+- Unused generic type `T` at unused_parameters.rue:3:29
+- Unused generic type `T` at unused_parameters.rue:27:19
diff --git a/tests/warnings/unused_statement_value.yaml b/tests/warnings/unused_statement_value.yaml
index 2553df55..f40de4a1 100644
--- a/tests/warnings/unused_statement_value.yaml
+++ b/tests/warnings/unused_statement_value.yaml
@@ -28,5 +28,5 @@ tests:
   byte_cost: 60000
   total_cost: 60545
 diagnostics:
-- Value returned by statement is unused at test:2:5
-- Value returned by statement is unused at test:14:5
+- Value returned by statement is unused at unused_statement_value.rue:2:5
+- Value returned by statement is unused at unused_statement_value.rue:14:5
diff --git a/tests/warnings/unused_symbols.yaml b/tests/warnings/unused_symbols.yaml
index 7885de13..7718fa4f 100644
--- a/tests/warnings/unused_symbols.yaml
+++ b/tests/warnings/unused_symbols.yaml
@@ -13,8 +13,8 @@ tests:
   byte_cost: 132000
   total_cost: 132142
 diagnostics:
-- Unused constant `UNUSED_IN_MODULE` at test:3:18
-- Unused constant `UNUSED` at test:29:7
-- Unused function `unused` at test:37:4
-- Unused binding `unused` at test:12:9
-- Unused binding `unused` at test:20:9
+- Unused constant `UNUSED_IN_MODULE` at unused_symbols.rue:3:18
+- Unused constant `UNUSED` at unused_symbols.rue:29:7
+- Unused function `unused` at unused_symbols.rue:37:4
+- Unused binding `unused` at unused_symbols.rue:12:9
+- Unused binding `unused` at unused_symbols.rue:20:9
diff --git a/tests/warnings/unused_types.yaml b/tests/warnings/unused_types.yaml
index e780e03e..bdb39e76 100644
--- a/tests/warnings/unused_types.yaml
+++ b/tests/warnings/unused_types.yaml
@@ -27,8 +27,8 @@ tests:
   byte_cost: 12000
   total_cost: 12044
 diagnostics:
-- Unused constant `UNUSED_VALUE` at test:10:7
-- Unused type alias `Recursive` at test:1:6
-- Unused type alias `Unused` at test:7:6
-- Unused struct `UnusedStruct` at test:16:8
-- Unused type alias `UnusedAlias` at test:21:6
+- Unused constant `UNUSED_VALUE` at unused_types.rue:10:7
+- Unused type alias `Recursive` at unused_types.rue:1:6
+- Unused type alias `Unused` at unused_types.rue:7:6
+- Unused struct `UnusedStruct` at unused_types.rue:16:8
+- Unused type alias `UnusedAlias` at unused_types.rue:21:6