adding unreachable

lang/README.md

@@ -190,6 +190,11 @@ main := fn(): uint {
 
 	if bar != null return 420
 
+	g := @as(?^uint, null)
+	g = a
+
+	_rd := *g
+
 	return d - *f.a
 }
 
@@ -458,6 +463,16 @@ main := fn(): uint {
 }
 ```
 
+#### die
+```hb
+main := fn(): never {
+	// simply emmits 'un' instruction that immediately terminates the execution
+	// the expression evaluates into `never` type that can coerce into any other
+	// type
+	die
+}
+```
+
 ### Incomplete Examples
 
 #### comptime_pointers
@@ -478,7 +493,7 @@ modify := fn($num: ^uint): void {
 MALLOC_SYS_CALL := 69
 FREE_SYS_CALL := 96
 
-malloc := fn(size: uint, align: uint): ^void return @eca(MALLOC_SYS_CALL, size, align)
+malloc := fn(size: uint, align: uint): ?^void return @eca(MALLOC_SYS_CALL, size, align)
 free := fn(ptr: ^void, size: uint, align: uint): void return @eca(FREE_SYS_CALL, ptr, size, align)
 
 Vec := fn($Elem: type): type {
@@ -497,7 +512,7 @@ deinit := fn($Elem: type, vec: ^Vec(Elem)): void {
 	return
 }
 
-push := fn($Elem: type, vec: ^Vec(Elem), value: Elem): ^Elem {
+push := fn($Elem: type, vec: ^Vec(Elem), value: Elem): ?^Elem {
 	if vec.len == vec.cap {
 		if vec.cap == 0 {
 			vec.cap = 1
@@ -505,11 +520,11 @@ push := fn($Elem: type, vec: ^Vec(Elem), value: Elem): ^Elem {
 			vec.cap *= 2
 		}
 
-		new_alloc := @as(^Elem, @bitcast(malloc(vec.cap * @sizeof(Elem), @alignof(Elem))))
+		new_alloc := @as(?^Elem, @bitcast(malloc(vec.cap * @sizeof(Elem), @alignof(Elem))))
-		if new_alloc == 0 return @bitcast(0)
+		if new_alloc == null return null
 
 		src_cursor := vec.data
-		dst_cursor := new_alloc
+		dst_cursor := @as(^Elem, new_alloc)
 		end := vec.data + vec.len
 
 		loop if src_cursor == end break else {

lang/src/fmt.rs

@@ -371,6 +371,7 @@ impl<'a> Formatter<'a> {
             }
             Expr::Bool { value, .. } => f.write_str(if value { "true" } else { "false" }),
             Expr::Idk { .. } => f.write_str("idk"),
+            Expr::Die { .. } => f.write_str("die"),
             Expr::Null { .. } => f.write_str("null"),
             Expr::BinOp {
                 left,

lang/src/lexer.rs

@@ -134,6 +134,7 @@ pub enum TokenKind {
     False,
     Null,
     Idk,
+    Die,
 
     Ctor,
     Tupl,
@@ -306,6 +307,7 @@ gen_token_kind! {
         False     = b"false",
         Null      = b"null",
         Idk       = b"idk",
+        Die       = b"die",
         #[punkt]
         Ctor   = ".{",
         Tupl   = ".(",

lang/src/lib.rs

@@ -1023,16 +1023,14 @@ trait TypeParser {
 
             let Some((Expr::BinOp { left, right, .. }, name)) = f.find_decl(id) else {
                 return match id {
-                    Ok(name) => {
+                    Ok(_) => ty::Id::NEVER,
-                        let name = files[from_file as usize].ident_str(name);
-                        self.report(from_file, pos, format_args!("undefined indentifier: {name}"))
-                    }
                     Err("main") => self.report(
                         from_file,
                         pos,
                         format_args!(
                             "missing main function in '{}', compiler can't \
-                        emmit libraries since such concept is not defined",
+                            emmit libraries since such concept is not defined \
+                            (minimal main function: `main := fn(): void {{}}`)",
                             f.path
                         ),
                     ),

lang/src/parser.rs

@@ -337,6 +337,7 @@ impl<'a, 'b> Parser<'a, 'b> {
             T::False => E::Bool { pos, value: false },
             T::Null => E::Null { pos },
             T::Idk => E::Idk { pos },
+            T::Die => E::Die { pos },
             T::DQuote => E::String { pos, literal: self.tok_str(token) },
             T::Packed => {
                 self.packed = true;
@@ -903,6 +904,10 @@ generate_expr! {
         Idk {
             pos: Pos,
         },
+        /// `'die'`
+        Die {
+            pos: Pos,
+        },
         /// `'@' Ident List('(', ',', ')', Expr)`
         Directive {
             pos:  Pos,

lang/src/son.rs

@@ -138,7 +138,7 @@ impl Nodes {
                 }
                 depth
             }
-            Kind::Start | Kind::End => 1,
+            Kind::Start | Kind::End | Kind::Die => 1,
             u => unreachable!("{u:?}"),
         };
 
@@ -805,6 +805,12 @@ impl Nodes {
 
                 if let K::CInt { value } = self[rhs].kind {
                     match (op, value) {
+                        (T::Eq, 0) if self[lhs].ty.is_pointer() || self[lhs].kind == Kind::Stck => {
+                            return Some(self.new_const(ty::Id::BOOL, 0));
+                        }
+                        (T::Ne, 0) if self[lhs].ty.is_pointer() || self[lhs].kind == Kind::Stck => {
+                            return Some(self.new_const(ty::Id::BOOL, 1));
+                        }
                         (T::Add | T::Sub | T::Shl, 0) | (T::Mul | T::Div, 1) => return Some(lhs),
                         (T::Mul, 0) => return Some(rhs),
                         _ => {}
@@ -1294,6 +1300,7 @@ impl Nodes {
             Kind::If => write!(out, "  if:      "),
             Kind::Region | Kind::Loop => writeln!(out, "      goto: {node}"),
             Kind::Return => write!(out, " ret:      "),
+            Kind::Die => write!(out, " die:      "),
             Kind::CInt { value } => write!(out, "cint: #{value:<4}"),
             Kind::Phi => write!(out, " phi:      "),
             Kind::Arg => write!(
@@ -1380,7 +1387,7 @@ impl Nodes {
                     }
                     node = cfg_index;
                 }
-                Kind::Return => {
+                Kind::Return | Kind::Die => {
                     node = self[node].outputs[0];
                 }
                 Kind::Then | Kind::Else | Kind::Entry => {
@@ -1578,6 +1585,8 @@ pub enum Kind {
     // [ctrl, ?value]
     Return,
     // [ctrl]
+    Die,
+    // [ctrl]
     CInt {
         value: i64,
     },
@@ -1620,6 +1629,7 @@ impl Kind {
             Self::Start
                 | Self::End
                 | Self::Return
+                | Self::Die
                 | Self::Entry
                 | Self::Then
                 | Self::Else
@@ -1631,7 +1641,7 @@ impl Kind {
     }
 
     fn ends_basic_block(&self) -> bool {
-        matches!(self, Self::Return | Self::If | Self::End)
+        matches!(self, Self::Return | Self::If | Self::End | Self::Die)
     }
 
     fn is_peeped(&self) -> bool {
@@ -2478,6 +2488,16 @@ impl<'a> Codegen<'a> {
 
                 None
             }
+            Expr::Die { .. } => {
+                self.ci.ctrl.set(
+                    self.ci.nodes.new_node_nop(ty::Id::VOID, Kind::Die, [self.ci.ctrl.get()]),
+                    &mut self.ci.nodes,
+                );
+
+                self.ci.nodes[NEVER].inputs.push(self.ci.ctrl.get());
+                self.ci.nodes[self.ci.ctrl.get()].outputs.push(NEVER);
+                None
+            }
             Expr::Field { target, name, pos } => {
                 let mut vtarget = self.raw_expr(target)?;
                 self.strip_var(&mut vtarget);
@@ -2553,20 +2573,20 @@ impl<'a> Codegen<'a> {
             }
             Expr::UnOp { op: TokenKind::Mul, val, pos } => {
                 let ctx = Ctx { ty: ctx.ty.map(|ty| self.tys.make_ptr(ty)) };
-                let mut val = self.expr_ctx(val, ctx)?;
+                let mut vl = self.expr_ctx(val, ctx)?;
 
-                self.unwrap_opt(pos, &mut val);
+                self.unwrap_opt(val.pos(), &mut vl);
 
-                let Some(base) = self.tys.base_of(val.ty) else {
+                let Some(base) = self.tys.base_of(vl.ty) else {
                     self.report(
                         pos,
-                        fa!("the '{}' can not be dereferneced", self.ty_display(val.ty)),
+                        fa!("the '{}' can not be dereferneced", self.ty_display(vl.ty)),
                     );
                     return Value::NEVER;
                 };
-                val.ptr = true;
+                vl.ptr = true;
-                val.ty = base;
+                vl.ty = base;
-                Some(val)
+                Some(vl)
             }
             Expr::UnOp { pos, op: op @ TokenKind::Sub, val } => {
                 let val =
@@ -2784,6 +2804,25 @@ impl<'a> Codegen<'a> {
                 val.ty = ty;
                 Some(val)
             }
+            Expr::Directive { name: "unwrap", args: [expr], .. } => {
+                let mut val = self.raw_expr(expr)?;
+                self.strip_var(&mut val);
+
+                let Some(ty) = self.tys.inner_of(val.ty) else {
+                    self.report(
+                        expr.pos(),
+                        fa!(
+                            "only optional types can be unwrapped ('{}' is not optional)",
+                            self.ty_display(val.ty)
+                        ),
+                    );
+                    return Value::NEVER;
+                };
+
+                self.unwrap_opt_unchecked(ty, val.ty, &mut val);
+                val.ty = ty;
+                Some(val)
+            }
             Expr::Directive { name: "intcast", args: [expr], pos } => {
                 let mut val = self.expr(expr)?;
 
@@ -4063,18 +4102,7 @@ impl<'a> Codegen<'a> {
         let oty = mem::replace(&mut opt.ty, ty);
         match ctrl_ty {
             ty::Id::LEFT_UNREACHABLE => {
-                if self.tys.nieche_of(ty).is_some() {
+                self.unwrap_opt_unchecked(ty, oty, opt);
-                    return;
-                }
-
-                let OptLayout { payload_offset, .. } = self.tys.opt_layout(ty);
-
-                match oty.loc(self.tys) {
-                    Loc::Reg => {}
-                    Loc::Stack => {
-                        opt.id = self.offset(opt.id, payload_offset);
-                    }
-                }
             }
             ty::Id::RIGHT_UNREACHABLE => {
                 self.report(pos, "the value is always null, some checks might need to be inverted");
@@ -4083,12 +4111,29 @@ impl<'a> Codegen<'a> {
                 self.report(
                     pos,
                     "can't prove the value is not 'null', \
-                    there is not nice syntax for bypassing this, sorry",
+                    use '@unwrap(<opt>)' if you believe compiler is stupid, \
+                    or explicitly check for null and handle it \
+                    ('if <opt> == null { /* handle */ } else { /* use opt */ }')",
                 );
             }
         }
     }
 
+    fn unwrap_opt_unchecked(&mut self, ty: ty::Id, oty: ty::Id, opt: &mut Value) {
+        if self.tys.nieche_of(ty).is_some() {
+            return;
+        }
+
+        let OptLayout { payload_offset, .. } = self.tys.opt_layout(ty);
+
+        match oty.loc(self.tys) {
+            Loc::Reg => {}
+            Loc::Stack => {
+                opt.id = self.offset(opt.id, payload_offset);
+            }
+        }
+    }
+
     fn gen_null_check(&mut self, mut cmped: Value, ty: ty::Id, op: TokenKind) -> Nid {
         let OptLayout { flag_ty, flag_offset, .. } = self.tys.opt_layout(ty);
 
@@ -4335,6 +4380,7 @@ mod tests {
         inline;
         idk;
         generic_functions;
+        die;
 
         // Incomplete Examples;
         //comptime_pointers;

lang/src/son/hbvm.rs

@@ -308,6 +308,9 @@ impl ItemCtx {
                             self.emit(instrs::jmp(0));
                         }
                     }
+                    Kind::Die => {
+                        self.emit(instrs::un());
+                    }
                     Kind::CInt { value } if node.ty.is_float() => {
                         self.emit(match node.ty {
                             ty::Id::F32 => instrs::li32(
@@ -617,7 +620,9 @@ impl ItemCtx {
             self.emit(instrs::addi64(reg::STACK_PTR, reg::STACK_PTR, (pushed + stack) as _));
         }
         self.relocs.iter_mut().for_each(|r| r.reloc.offset -= stripped_prelude_size as u32);
-        self.emit(instrs::jala(reg::ZERO, reg::RET_ADDR, 0));
+        if sig.ret != ty::Id::NEVER {
+            self.emit(instrs::jala(reg::ZERO, reg::RET_ADDR, 0));
+        }
     }
 }
 
@@ -822,6 +827,10 @@ impl<'a> Function<'a> {
                 self.add_instr(nid, ops);
                 self.emit_node(node.outputs[0], nid);
             }
+            Kind::Die => {
+                self.add_instr(nid, vec![]);
+                self.emit_node(node.outputs[0], nid);
+            }
             Kind::CInt { .. }
                 if node.outputs.iter().all(|&o| {
                     let ond = &self.nodes[o];
@@ -1167,7 +1176,7 @@ impl regalloc2::Function for Function<'_> {
     }
 
     fn is_ret(&self, insn: regalloc2::Inst) -> bool {
-        self.nodes[self.instrs[insn.index()].nid].kind == Kind::Return
+        matches!(self.nodes[self.instrs[insn.index()].nid].kind, Kind::Return | Kind::Die)
     }
 
     fn is_branch(&self, insn: regalloc2::Inst) -> bool {

lang/tests/son_tests_die.txt

@@ -0,0 +1,5 @@
+main:
+    UN 
+code size: 9
+ret: 0
+status: Err(Unreachable)

lang/tests/son_tests_generic_types.txt

@@ -75,52 +75,53 @@ push:
     MUL64 r2, r36, r37
     CP r3, r37
     JAL r31, r0, :malloc
-    CP r38, r34
+    CP r38, r1
-    ST r36, r38, 16a, 8h
+    CP r39, r34
-    JNE r1, r35, :3
+    ST r36, r39, 16a, 8h
-    CP r1, r35
+    LI64 r1, 0d
+    CP r7, r38
+    JNE r7, r1, :3
     JMP :4
- 3: CP r39, r1
+ 3: CP r38, r7
-    CP r1, r35
+    LD r8, r39, 8a, 8h
-    LD r6, r38, 8a, 8h
+    MULI64 r10, r8, 8d
-    MULI64 r8, r6, 8d
+    LD r3, r39, 0a, 8h
-    LD r12, r38, 0a, 8h
+    ADD64 r7, r3, r10
-    ADD64 r11, r12, r8
+    CP r5, r38
-    CP r3, r39
+ 9: LD r2, r39, 0a, 8h
- 9: LD r2, r38, 0a, 8h
+    LD r10, r39, 8a, 8h
-    LD r8, r38, 8a, 8h
+    JNE r7, r3, :5
-    JNE r11, r12, :5
+    JEQ r10, r35, :6
-    JEQ r8, r1, :6
     CP r4, r37
-    MUL64 r3, r8, r4
+    MUL64 r3, r10, r4
     JAL r31, r0, :free
-    CP r5, r39
+    CP r6, r38
     JMP :7
- 6: CP r5, r39
+ 6: CP r6, r38
- 7: ST r5, r38, 0a, 8h
+ 7: ST r6, r39, 0a, 8h
     JMP :8
  5: CP r4, r37
-    CP r5, r39
+    CP r6, r38
-    ADDI64 r6, r3, 8d
+    ADDI64 r8, r5, 8d
-    ADDI64 r7, r12, 8d
+    ADDI64 r9, r3, 8d
-    LD r8, r12, 0a, 8h
+    LD r10, r3, 0a, 8h
-    ST r8, r3, 0a, 8h
+    ST r10, r5, 0a, 8h
-    CP r3, r6
+    CP r3, r9
-    CP r12, r7
+    CP r5, r8
     JMP :9
- 0: CP r38, r34
+ 0: CP r39, r34
- 8: LD r3, r38, 8a, 8h
+ 8: LD r5, r39, 8a, 8h
-    MULI64 r5, r3, 8d
+    MULI64 r7, r5, 8d
-    LD r4, r38, 0a, 8h
+    LD r6, r39, 0a, 8h
-    ADD64 r1, r4, r5
+    ADD64 r1, r6, r7
     CP r3, r32
     ST r3, r1, 0a, 8h
-    LD r11, r38, 8a, 8h
+    LD r2, r39, 8a, 8h
-    ADD64 r2, r11, r33
+    ADD64 r3, r2, r33
-    ST r2, r38, 8a, 8h
+    ST r3, r39, 8a, 8h
  4: LD r31, r254, 0a, 72h
     ADDI64 r254, r254, 72d
     JALA r0, r31, 0a
-code size: 945
+code size: 955
 ret: 69
 status: Ok(())