Implement void returns

examples/hello_world.reid

@@ -7,7 +7,7 @@ import std::new_string;
 import std::add_num_to_str;
 import std::concat_strings;
 
-fn main() -> u8 {
+fn main() {
     let mut test = from_str("hello");
 
     concat_strings(&mut test, from_str(" world"));
@@ -21,5 +21,5 @@ fn main() -> u8 {
 
     free_string(&test);
 
-    return 8;
+    return;
 }

reid/src/allocator.rs

@@ -89,8 +89,10 @@ impl mir::Block {
         }
 
         if let Some((_, ret_expr)) = &self.return_expression {
+            if let Some(ret_expr) = ret_expr {
                 allocated.extend(ret_expr.allocate(scope));
             }
+        }
 
         allocated
     }

reid/src/ast/mod.rs

@@ -164,7 +164,7 @@ pub struct StructExpression {
 #[derive(Debug, Clone)]
 pub struct Block(
     pub Vec<BlockLevelStatement>,
-    pub Option<(ReturnType, Expression)>,
+    pub Option<(ReturnType, Option<Expression>)>,
     pub TokenRange,
 );
 
@@ -177,7 +177,7 @@ pub enum BlockLevelStatement {
         _i: ImportStatement,
     },
     Expression(Expression),
-    Return(ReturnType, Expression),
+    Return(ReturnType, Option<Expression>),
     ForLoop(String, TokenRange, Expression, Expression, Block),
     WhileLoop(Expression, Block),
 }

reid/src/ast/parse.rs

@@ -556,7 +556,7 @@ impl Parse for Block {
         stream.expect(Token::BraceOpen)?;
 
         while !matches!(stream.peek(), Some(Token::BraceClose)) {
-            if let Some((_, e)) = return_stmt.take() {
+            if let Some((_, Some(e))) = return_stmt.take() {
                 // Special list of expressions that are simply not warned about,
                 // if semicolon is missing.
                 if !matches!(e, Expression(ExpressionKind::IfExpr(_), _)) {
@@ -697,7 +697,7 @@ impl Parse for BlockLevelStatement {
             },
             Some(Token::ReturnKeyword) => {
                 stream.next();
-                let exp = stream.parse()?;
+                let exp = stream.parse().ok();
                 stream.expect(Token::Semi)?;
                 Stmt::Return(ReturnType::Hard, exp)
             }
@@ -717,7 +717,7 @@ impl Parse for BlockLevelStatement {
                     if stream.expect(Token::Semi).is_ok() {
                         Stmt::Expression(e)
                     } else {
-                        Stmt::Return(ReturnType::Soft, e)
+                        Stmt::Return(ReturnType::Soft, Some(e))
                     }
                 }
             }

reid/src/ast/process.rs

@@ -3,8 +3,8 @@ use std::path::PathBuf;
 use crate::{
     ast::{self},
     mir::{
-        self, CustomTypeKey, ModuleMap, NamedVariableRef, SourceModuleId, StmtKind, StructField,
+        self, CustomTypeKey, ModuleMap, NamedVariableRef, ReturnKind, SourceModuleId, StmtKind,
-        StructType, WhileStatement,
+        StructField, StructType, WhileStatement,
     },
 };
 
@@ -166,7 +166,11 @@ impl ast::Block {
                     (StmtKind::Expression(e.process(module_id)), e.1)
                 }
                 ast::BlockLevelStatement::Return(_, e) => {
+                    if let Some(e) = e {
                         (StmtKind::Expression(e.process(module_id)), e.1)
+                    } else {
+                        panic!(); // Should never happen?
+                    }
                 }
                 ast::BlockLevelStatement::ForLoop(counter, counter_range, start, end, block) => {
                     let counter_var = NamedVariableRef(
@@ -249,7 +253,11 @@ impl ast::Block {
         }
 
         let return_expression = if let Some(r) = &self.1 {
-            Some((r.0.into(), Box::new(r.1.process(module_id))))
+            if let Some(expr) = &r.1 {
+                Some((r.0.into(), Some(Box::new(expr.process(module_id)))))
+            } else {
+                Some((ReturnKind::Hard, None))
+            }
         } else {
             None
         };

reid/src/codegen.rs

@@ -632,14 +632,14 @@ impl FunctionDefinitionKind {
                 }
 
                 if let Some(debug) = &scope.debug {
-                    let location = &block
+                    if let Some(location) =
-                        .return_meta()
+                        &block.return_meta().into_debug(scope.tokens, debug.scope)
-                        .into_debug(scope.tokens, debug.scope)
+                    {
-                        .unwrap();
                         let location = debug.info.location(&debug.scope, *location);
                         scope.block.set_terminator_location(location).unwrap();
                     }
                 }
+            }
             mir::FunctionDefinitionKind::Extern(_) => {}
             mir::FunctionDefinitionKind::Intrinsic(_) => {}
         };
@@ -664,6 +664,7 @@ impl mir::Block {
         }
 
         if let Some((kind, expr)) = &self.return_expression {
+            if let Some(expr) = expr {
                 let ret = expr.codegen(&mut scope, &mut state.load(true))?;
                 match kind {
                     mir::ReturnKind::Hard => {
@@ -676,6 +677,13 @@ impl mir::Block {
                     }
                     mir::ReturnKind::Soft => Ok(ret),
                 }
+            } else {
+                match kind {
+                    mir::ReturnKind::Hard => scope.block.terminate(Term::RetVoid).unwrap(),
+                    mir::ReturnKind::Soft => {}
+                }
+                Ok(None)
+            }
         } else {
             Ok(None)
         }

reid/src/mir/fmt.rs

@@ -142,9 +142,15 @@ impl Display for Block {
             write!(inner_f, "{}", statement)?;
         }
         if let Some(ret) = &self.return_expression {
+            let ret_fmt = if let Some(ret) = &ret.1 {
+                format!("{}", ret)
+            } else {
+                String::from("void")
+            };
+
             match ret.0 {
-                ReturnKind::Hard => writeln!(inner_f, "Return(Hard): {}", ret.1),
+                ReturnKind::Hard => writeln!(inner_f, "Return(Hard): {}", ret_fmt),
-                ReturnKind::Soft => writeln!(inner_f, "Return(Soft): {}", ret.1),
+                ReturnKind::Soft => writeln!(inner_f, "Return(Soft): {}", ret_fmt),
             }?;
         } else {
             writeln!(inner_f, "No Return")?;

reid/src/mir/implement.rs

@@ -367,7 +367,7 @@ impl StructType {
 
 enum BlockReturn<'b> {
     Early(&'b Statement),
-    Normal(ReturnKind, &'b Expression),
+    Normal(ReturnKind, &'b Option<Box<Expression>>),
 }
 
 impl Block {
@@ -394,7 +394,7 @@ impl Block {
     pub fn return_meta(&self) -> Metadata {
         self.return_expression
             .as_ref()
-            .map(|e| e.1 .1)
+            .map(|e| e.1.as_ref().map(|e| e.1).unwrap_or(Metadata::default()))
             .or(self.statements.last().map(|s| s.1))
             .unwrap_or(self.meta)
     }
@@ -420,18 +420,30 @@ impl Block {
         self.return_expression
             .as_ref()
             .ok_or(ReturnTypeOther::NoBlockReturn(self.meta))
-            .and_then(|(kind, stmt)| Ok((*kind, stmt.return_type(refs, mod_id)?.1)))
+            .and_then(|(kind, stmt)| {
+                Ok((
+                    *kind,
+                    stmt.as_ref()
+                        .and_then(|s| s.return_type(refs, mod_id).ok())
+                        .map(|s| s.1)
+                        .unwrap_or(TypeKind::Void),
+                ))
+            })
     }
 
     pub fn backing_var(&self) -> Option<&NamedVariableRef> {
         match self.return_expr().ok()? {
             BlockReturn::Early(statement) => statement.backing_var(),
             BlockReturn::Normal(kind, expr) => {
+                if let Some(expr) = expr {
                     if kind == ReturnKind::Soft {
                         expr.backing_var()
                     } else {
                         None
                     }
+                } else {
+                    None
+                }
             }
         }
     }

reid/src/mir/mod.rs

@@ -328,7 +328,7 @@ impl FunctionDefinition {
 pub struct Block {
     /// List of non-returning statements
     pub statements: Vec<Statement>,
-    pub return_expression: Option<(ReturnKind, Box<Expression>)>,
+    pub return_expression: Option<(ReturnKind, Option<Box<Expression>>)>,
     pub meta: Metadata,
 }
 

reid/src/mir/typecheck.rs

@@ -462,11 +462,15 @@ impl Block {
                 ReturnKind::Hard => state.scope.return_type_hint.clone(),
                 ReturnKind::Soft => hint_t.cloned(),
             };
+            if let Some(expr) = expr {
                 let res = expr.typecheck(&mut state, &typerefs, ret_hint_t.as_ref());
                 Ok((
                     *return_kind,
                     state.or_else(res, TypeKind::Vague(Vague::Unknown), expr.1),
                 ))
+            } else {
+                Ok((*return_kind, TypeKind::Void))
+            }
         } else {
             Ok((ReturnKind::Soft, TypeKind::Void))
         }

reid/src/mir/typeinference.rs

@@ -266,8 +266,10 @@ impl Block {
 
         // If there is a return expression, infer it's type
         if let Some(ret_expr) = &mut self.return_expression {
-            let ret_res = ret_expr.1.infer_types(&mut state, &inner_refs);
+            if let Some(expr) = &mut ret_expr.1 {
-            state.ok(ret_res, ret_expr.1 .1);
+                let ret_res = expr.infer_types(&mut state, &inner_refs);
+                state.ok(ret_res, expr.1);
+            }
         }
 
         // Fetch the declared return type

reid/tests/e2e.rs

@@ -17,7 +17,7 @@ use util::assert_err;
 
 mod util;
 
-fn test(source: &str, name: &str, expected_exit_code: i32) {
+fn test(source: &str, name: &str, expected_exit_code: Option<i32>) {
     assert_err(assert_err(std::panic::catch_unwind(|| {
         let mut map = Default::default();
         let (id, tokens) = assert_err(parse_module(source, name, &mut map));
@@ -50,7 +50,9 @@ fn test(source: &str, name: &str, expected_exit_code: i32) {
         let executed = Command::new(&out_path).output();
         std::fs::remove_file(out_path).unwrap();
 
+        if let Some(expected_exit_code) = expected_exit_code {
             assert_eq!(expected_exit_code, executed.unwrap().status.code().unwrap());
+        }
 
         Ok::<(), ()>(())
     })))
@@ -58,81 +60,125 @@ fn test(source: &str, name: &str, expected_exit_code: i32) {
 
 #[test]
 fn arithmetic_compiles_well() {
-    test(include_str!("../../examples/arithmetic.reid"), "test", 48);
+    test(
+        include_str!("../../examples/arithmetic.reid"),
+        "test",
+        Some(48),
+    );
 }
 #[test]
 fn array_structs_compiles_well() {
-    test(include_str!("../../examples/array_structs.reid"), "test", 5);
+    test(
+        include_str!("../../examples/array_structs.reid"),
+        "test",
+        Some(5),
+    );
 }
 #[test]
 fn array_compiles_well() {
-    test(include_str!("../../examples/array.reid"), "test", 3);
+    test(include_str!("../../examples/array.reid"), "test", Some(3));
 }
 #[test]
 fn borrow_compiles_well() {
-    test(include_str!("../../examples/borrow.reid"), "test", 17);
+    test(include_str!("../../examples/borrow.reid"), "test", Some(17));
 }
 #[test]
 fn borrow_hard_compiles_well() {
-    test(include_str!("../../examples/borrow_hard.reid"), "test", 17);
+    test(
+        include_str!("../../examples/borrow_hard.reid"),
+        "test",
+        Some(17),
+    );
 }
 #[test]
 fn cast_compiles_well() {
-    test(include_str!("../../examples/cast.reid"), "test", 6);
+    test(include_str!("../../examples/cast.reid"), "test", Some(6));
 }
 #[test]
 fn char_compiles_well() {
-    test(include_str!("../../examples/char.reid"), "test", 98);
+    test(include_str!("../../examples/char.reid"), "test", Some(98));
 }
 #[test]
 fn div_mod_compiles_well() {
-    test(include_str!("../../examples/div_mod.reid"), "test", 12);
+    test(
+        include_str!("../../examples/div_mod.reid"),
+        "test",
+        Some(12),
+    );
 }
 #[test]
 fn fibonacci_compiles_well() {
-    test(include_str!("../../examples/fibonacci.reid"), "test", 1);
+    test(
+        include_str!("../../examples/fibonacci.reid"),
+        "test",
+        Some(1),
+    );
 }
 #[test]
 fn float_compiles_well() {
-    test(include_str!("../../examples/float.reid"), "test", 1);
+    test(include_str!("../../examples/float.reid"), "test", Some(1));
 }
 #[test]
 fn hello_world_compiles_well() {
-    test(include_str!("../../examples/hello_world.reid"), "test", 8);
+    test(
+        include_str!("../../examples/hello_world.reid"),
+        "test",
+        None,
+    );
 }
 #[test]
 fn mutable_compiles_well() {
-    test(include_str!("../../examples/mutable.reid"), "test", 21);
+    test(
+        include_str!("../../examples/mutable.reid"),
+        "test",
+        Some(21),
+    );
 }
 #[test]
 fn ptr_compiles_well() {
-    test(include_str!("../../examples/ptr.reid"), "test", 5);
+    test(include_str!("../../examples/ptr.reid"), "test", Some(5));
 }
 #[test]
 fn std_test_compiles_well() {
-    test(include_str!("../../examples/std_test.reid"), "test", 3);
+    test(
+        include_str!("../../examples/std_test.reid"),
+        "test",
+        Some(3),
+    );
 }
 #[test]
 fn strings_compiles_well() {
-    test(include_str!("../../examples/strings.reid"), "test", 5);
+    test(include_str!("../../examples/strings.reid"), "test", Some(5));
 }
 #[test]
 fn struct_compiles_well() {
-    test(include_str!("../../examples/struct.reid"), "test", 17);
+    test(include_str!("../../examples/struct.reid"), "test", Some(17));
 }
 #[test]
 fn loops_compiles_well() {
-    test(include_str!("../../examples/loops.reid"), "test", 10);
+    test(include_str!("../../examples/loops.reid"), "test", Some(10));
 }
 #[test]
 fn ptr_hard_compiles_well() {
-    test(include_str!("../../examples/ptr_hard.reid"), "test", 0);
+    test(
+        include_str!("../../examples/ptr_hard.reid"),
+        "test",
+        Some(0),
+    );
 }
 #[test]
 fn loop_hard_compiles_well() {
-    test(include_str!("../../examples/loop_hard.reid"), "test", 0);
+    test(
+        include_str!("../../examples/loop_hard.reid"),
+        "test",
+        Some(0),
+    );
 }
 #[test]
 fn custom_binop_compiles_well() {
-    test(include_str!("../../examples/custom_binop.reid"), "test", 21);
+    test(
+        include_str!("../../examples/custom_binop.reid"),
+        "test",
+        Some(21),
+    );
 }