Fix #247

compiler/erg_compiler/context/hint.rs

@@ -57,8 +57,8 @@ impl Context {
                 found.union_types()
                     .map(|(t1, t2)| format!("cannot {verb} {t1} {preposition} {t2}"))
                     .or_else(|| {
-                        let ts = expected.inner_ts();
-                        Some(format!("cannot {verb} {found} {preposition} {}", ts[0]))
+                        let expected_inner = Self::readable_type(&expected.inner_ts()[0]);
+                        Some(format!("cannot {verb} {found} {preposition} {expected_inner}"))
                     })
             }
         }

compiler/erg_compiler/context/inquire.rs

@@ -849,7 +849,7 @@ impl Context {
     /// substitute_call(instance: ((?T, Int) -> ?T), [Int, Nat], []) => instance: (Int, Int) -> Str
     /// substitute_call(instance: ((?M(: Nat)..?N(: Nat)) -> ?M+?N), [1..2], []) => instance: (1..2) -> {3}
     /// substitute_call(instance: ((?L(: Add(?R, ?O)), ?R) -> ?O), [1, 2], []) => instance: (Nat, Nat) -> Nat
-    /// substitute_call(instance: ?T, [Int, Str], []) => instance: (Int, Str) -> Int
+    /// substitute_call(instance: ((Failure, ?T) -> ?T), [Int, Int]) => instance: (Failure, Int) -> Int
     /// ```
     fn substitute_call(
         &self,

compiler/erg_compiler/context/instantiate.rs

@@ -205,31 +205,47 @@ impl Context {
         sig: &ast::SubrSignature,
         default_ts: Vec<Type>,
         mode: RegistrationMode,
-    ) -> TyCheckResult<Type> {
+    ) -> Result<Type, (TyCheckErrors, Type)> {
+        let mut errs = TyCheckErrors::empty();
         // -> Result<Type, (Type, TyCheckErrors)> {
         let opt_decl_sig_t = self
             .rec_get_decl_info(&sig.ident, AccessKind::Name, &self.cfg.input, &self.name)
             .ok()
             .map(|vi| enum_unwrap!(vi.t, Type::Subr));
-        let mut tmp_tv_cache = self.instantiate_ty_bounds(&sig.bounds, PreRegister)?;
+        let mut tmp_tv_cache = self
+            .instantiate_ty_bounds(&sig.bounds, PreRegister)
+            .map_err(|errs| (errs, Type::Failure))?;
         let mut non_defaults = vec![];
-        for (n, p) in sig.params.non_defaults.iter().enumerate() {
+        for (n, param) in sig.params.non_defaults.iter().enumerate() {
             let opt_decl_t = opt_decl_sig_t
                 .as_ref()
                 .and_then(|subr| subr.non_default_params.get(n));
-            non_defaults.push(self.instantiate_param_ty(
-                p,
-                None,
-                opt_decl_t,
-                &mut tmp_tv_cache,
-                mode,
-            )?);
+            match self.instantiate_param_ty(param, None, opt_decl_t, &mut tmp_tv_cache, mode) {
+                Ok(t) => non_defaults.push(t),
+                Err(es) => {
+                    errs.extend(es);
+                    non_defaults.push(ParamTy::pos(param.inspect().cloned(), Type::Failure));
+                }
+            }
         }
         let var_args = if let Some(var_args) = sig.params.var_args.as_ref() {
             let opt_decl_t = opt_decl_sig_t
                 .as_ref()
                 .and_then(|subr| subr.var_params.as_ref().map(|v| v.as_ref()));
-            Some(self.instantiate_param_ty(var_args, None, opt_decl_t, &mut tmp_tv_cache, mode)?)
+            let pt = match self.instantiate_param_ty(
+                var_args,
+                None,
+                opt_decl_t,
+                &mut tmp_tv_cache,
+                mode,
+            ) {
+                Ok(pt) => pt,
+                Err(es) => {
+                    errs.extend(es);
+                    ParamTy::pos(var_args.inspect().cloned(), Type::Failure)
+                }
+            };
+            Some(pt)
         } else {
             None
         };
@@ -238,19 +254,32 @@ impl Context {
             let opt_decl_t = opt_decl_sig_t
                 .as_ref()
                 .and_then(|subr| subr.default_params.get(n));
-            defaults.push(self.instantiate_param_ty(
+            match self.instantiate_param_ty(
                 &p.sig,
                 Some(default_t),
                 opt_decl_t,
                 &mut tmp_tv_cache,
                 mode,
-            )?);
+            ) {
+                Ok(t) => defaults.push(t),
+                Err(es) => {
+                    errs.extend(es);
+                    defaults.push(ParamTy::pos(p.sig.inspect().cloned(), Type::Failure));
+                }
+            }
         }
         let spec_return_t = if let Some(s) = sig.return_t_spec.as_ref() {
             let opt_decl_t = opt_decl_sig_t
                 .as_ref()
                 .map(|subr| ParamTy::anonymous(subr.return_t.as_ref().clone()));
-            self.instantiate_typespec(s, opt_decl_t.as_ref(), &mut tmp_tv_cache, mode, false)?
+            match self.instantiate_typespec(s, opt_decl_t.as_ref(), &mut tmp_tv_cache, mode, false)
+            {
+                Ok(ty) => ty,
+                Err(es) => {
+                    errs.extend(es);
+                    Type::Failure
+                }
+            }
         } else {
             // preregisterならouter scopeで型宣言(see inference.md)
             let level = if mode == PreRegister {
@@ -260,11 +289,16 @@ impl Context {
             };
             free_var(level, Constraint::new_type_of(Type))
         };
-        Ok(if sig.ident.is_procedural() {
+        let typ = if sig.ident.is_procedural() {
             proc(non_defaults, var_args, defaults, spec_return_t)
         } else {
             func(non_defaults, var_args, defaults, spec_return_t)
-        })
+        };
+        if errs.is_empty() {
+            Ok(typ)
+        } else {
+            Err((errs, typ))
+        }
     }
 
     /// spec_t == Noneかつリテラル推論が不可能なら型変数を発行する
@@ -454,12 +488,12 @@ impl Context {
                     tmp_tv_cache.push_or_init_tyvar(&Str::rc(other), &tyvar);
                     Ok(tyvar)
                 } else {
-                    Err(TyCheckErrors::from(TyCheckError::no_var_error(
+                    Err(TyCheckErrors::from(TyCheckError::no_type_error(
                         self.cfg.input.clone(),
                         line!() as usize,
                         simple.loc(),
                         self.caused_by(),
-                        &format!("(Type) {other}"),
+                        other,
                         self.get_similar_name(other),
                     )))
                 }
@@ -468,12 +502,12 @@ impl Context {
                 let ctx = if let Some((_, ctx)) = self.rec_get_type(other) {
                     ctx
                 } else {
-                    return Err(TyCheckErrors::from(TyCheckError::no_var_error(
+                    return Err(TyCheckErrors::from(TyCheckError::no_type_error(
                         self.cfg.input.clone(),
                         line!() as usize,
                         simple.ident.loc(),
                         self.caused_by(),
-                        &format!("(Type) {other}"),
+                        other,
                         self.get_similar_name(other),
                     )));
                 };

compiler/erg_compiler/context/register.rs

@@ -115,21 +115,10 @@ impl Context {
             .collect::<Set<_>>();
         let default_ts =
             vec![free_var(self.level, Constraint::new_type_of(Type::Type)); sig.params.len()];
-        let t = self
-            .instantiate_sub_sig_t(sig, default_ts, PreRegister)
-            .map_err(|e| {
-                let vi = VarInfo::new(
-                    Type::Failure,
-                    muty,
-                    vis,
-                    kind.clone(),
-                    Some(comptime_decos.clone()),
-                    self.impl_of(),
-                    None,
-                );
-                self.decls.insert(sig.ident.name.clone(), vi);
-                e
-            })?;
+        let (errs, t) = match self.instantiate_sub_sig_t(sig, default_ts, PreRegister) {
+            Ok(t) => (TyCheckErrors::empty(), t),
+            Err((errs, t)) => (errs, t),
+        };
         let vi = VarInfo::new(
             t,
             muty,
@@ -149,7 +138,11 @@ impl Context {
             )))
         } else {
             self.decls.insert(sig.ident.name.clone(), vi);
+            if errs.is_empty() {
                 Ok(())
+            } else {
+                Err(errs)
+            }
         }
     }
 
@@ -345,6 +338,7 @@ impl Context {
         params: &hir::Params,
         opt_decl_subr_t: Option<SubrType>,
     ) -> TyCheckResult<()> {
+        let mut errs = TyCheckErrors::empty();
         if let Some(decl_subr_t) = opt_decl_subr_t {
             assert_eq!(
                 params.non_defaults.len(),
@@ -356,24 +350,36 @@ impl Context {
                 .iter()
                 .zip(decl_subr_t.non_default_params.iter())
             {
-                self.assign_param(sig, false, Some(pt))?;
+                if let Err(es) = self.assign_param(sig, false, Some(pt)) {
+                    errs.extend(es);
+                }
             }
             for (sig, pt) in params
                 .defaults
                 .iter()
                 .zip(decl_subr_t.default_params.iter())
             {
-                self.assign_param(&sig.sig, true, Some(pt))?;
+                if let Err(es) = self.assign_param(&sig.sig, true, Some(pt)) {
+                    errs.extend(es);
+                }
             }
         } else {
             for sig in params.non_defaults.iter() {
-                self.assign_param(sig, false, None)?;
+                if let Err(es) = self.assign_param(sig, false, None) {
+                    errs.extend(es);
+                }
             }
             for sig in params.defaults.iter() {
-                self.assign_param(&sig.sig, true, None)?;
+                if let Err(es) = self.assign_param(&sig.sig, true, None) {
+                    errs.extend(es);
                 }
             }
+        }
+        if errs.is_empty() {
             Ok(())
+        } else {
+            Err(errs)
+        }
     }
 
     /// ## Errors

compiler/erg_compiler/context/tyvar.rs

@@ -1268,6 +1268,10 @@ impl Context {
         if maybe_sub == &Type::Never || maybe_sup == &Type::Obj || maybe_sup == maybe_sub {
             return Ok(());
         }
+        // API definition was failed and inspection is useless after this
+        if maybe_sub == &Type::Failure || maybe_sup == &Type::Failure {
+            return Ok(());
+        }
         self.occur(maybe_sub, maybe_sup, loc)?;
         let maybe_sub_is_sub = self.subtype_of(maybe_sub, maybe_sup);
         if maybe_sub.has_no_unbound_var() && maybe_sup.has_no_unbound_var() && maybe_sub_is_sub {

compiler/erg_compiler/error.rs

@@ -1577,6 +1577,43 @@ impl LowerError {
         )
     }
 
+    pub fn no_type_error(
+        input: Input,
+        errno: usize,
+        loc: Location,
+        caused_by: String,
+        name: &str,
+        similar_name: Option<&str>,
+    ) -> Self {
+        let name = readable_name(name);
+        let hint = similar_name.map(|n| {
+            let n = StyledStr::new(n, Some(HINT), Some(ATTR));
+            switch_lang!(
+                "japanese" => format!("似た名前の型があります: {n}"),
+                "simplified_chinese" => format!("存在相同名称类型: {n}"),
+                "traditional_chinese" => format!("存在相同名稱類型: {n}"),
+                "english" => format!("exists a similar name type: {n}"),
+            )
+        });
+        let found = StyledString::new(name, Some(ERR), Some(ATTR));
+        Self::new(
+            ErrorCore::new(
+                vec![SubMessage::ambiguous_new(loc, vec![], hint)],
+                switch_lang!(
+                    "japanese" => format!("{found}という型は定義されていません"),
+                    "simplified_chinese" => format!("{found}未定义"),
+                    "traditional_chinese" => format!("{found}未定義"),
+                    "english" => format!("Type {found} is not defined"),
+                ),
+                errno,
+                NameError,
+                loc,
+            ),
+            input,
+            caused_by,
+        )
+    }
+
     pub fn type_not_found(
         input: Input,
         errno: usize,

compiler/erg_compiler/lib/std/_erg_nat.py

@@ -1,7 +1,7 @@
 from _erg_result import Error
 
 class Nat(int):
-    def try_new(i: int): # -> Result[Nat]
+    def try_new(i): # -> Result[Nat]
         if i >= 0:
             return Nat(i)
         else:
@@ -10,3 +10,9 @@ class Nat(int):
     def times(self, f):
         for _ in range(self):
             f()
+
+    def saturating_sub(self, other):
+        if self > other:
+            return self - other
+        else:
+            return 0

compiler/erg_compiler/lower.rs

@@ -835,11 +835,19 @@ impl ASTLowerer {
 
     fn lower_params(&mut self, params: ast::Params) -> LowerResult<hir::Params> {
         log!(info "entered {}({})", fn_name!(), params);
+        let mut errs = LowerErrors::empty();
         let mut hir_defaults = vec![];
         for default in params.defaults.into_iter() {
-            let default_val = self.lower_expr(default.default_val)?;
+            match self.lower_expr(default.default_val) {
+                Ok(default_val) => {
                     hir_defaults.push(hir::DefaultParamSignature::new(default.sig, default_val));
                 }
+                Err(es) => errs.extend(es),
+            }
+        }
+        if !errs.is_empty() {
+            Err(errs)
+        } else {
             let hir_params = hir::Params::new(
                 params.non_defaults,
                 params.var_args,
@@ -848,6 +856,7 @@ impl ASTLowerer {
             );
             Ok(hir_params)
         }
+    }
 
     /// TODO: varargs
     fn lower_lambda(&mut self, lambda: ast::Lambda) -> LowerResult<hir::Lambda> {

tests/should_err/addition.er

@@ -0,0 +1,4 @@
+add x, y =
+    x + y
+
+print! add("a", 1) # this will be an error

tests/should_err/invalid_param.er

@@ -0,0 +1,7 @@
+# Typo: Inu
+add x: Int, y: Inu, z: Int = x + y + z
+
+# 3rd arg is wrong
+print! add(1, 2, "")
+# missing argument
+print! add(1, 2)

tests/should_ok/addition.er

@@ -4,4 +4,3 @@ add x, y =
 print! add(1, 1)
 print! add(1.0, 1)
 print! add("a", "b")
-print! add("a", 1) # this will be an error

tests/test.rs

@@ -10,13 +10,13 @@ use erg_compiler::error::CompileErrors;
 use erg::DummyVM;
 
 #[test]
-fn exec_addition() -> Result<(), ()> {
-    expect_failure("tests/addition.er", 1)
+fn exec_addition_ok() -> Result<(), ()> {
+    expect_success("tests/should_ok/addition.er")
 }
 
 #[test]
 fn exec_advanced_type_spec() -> Result<(), ()> {
-    expect_success("tests/advanced_type_spec.er")
+    expect_success("tests/should_ok/advanced_type_spec.er")
 }
 
 #[test]
@@ -31,7 +31,7 @@ fn exec_class() -> Result<(), ()> {
 
 #[test]
 fn exec_control() -> Result<(), ()> {
-    expect_success("tests/control.er")
+    expect_success("tests/should_ok/control.er")
 }
 
 #[test]
@@ -66,31 +66,17 @@ fn exec_import() -> Result<(), ()> {
 
 #[test]
 fn exec_infer_class() -> Result<(), ()> {
-    expect_success("tests/infer_class.er")
+    expect_success("tests/should_ok/infer_class.er")
 }
 
 #[test]
 fn exec_infer_trait() -> Result<(), ()> {
-    expect_success("tests/infer_trait.er")
-}
-
-#[test]
-fn exec_move_check() -> Result<(), ()> {
-    expect_failure("examples/move_check.er", 1)
+    expect_success("tests/should_ok/infer_trait.er")
 }
 
 #[test]
 fn exec_pattern() -> Result<(), ()> {
-    expect_success("tests/pattern.er")
-}
-
-#[test]
-fn exec_pyimport() -> Result<(), ()> {
-    if cfg!(unix) {
-        expect_end_with("examples/pyimport.er", 111)
-    } else {
-        expect_failure("examples/pyimport.er", 1)
-    }
+    expect_success("tests/should_ok/pattern.er")
 }
 
 #[test]
@@ -103,32 +89,11 @@ fn exec_raw_ident() -> Result<(), ()> {
     expect_success("examples/raw_ident.er")
 }
 
-#[test]
-fn exec_rec() -> Result<(), ()> {
-    // this script is valid but the current code generating process has a bug.
-    expect_end_with("tests/rec.er", 1)
-}
-
 #[test]
 fn exec_record() -> Result<(), ()> {
     expect_success("examples/record.er")
 }
 
-#[test]
-fn exec_set() -> Result<(), ()> {
-    expect_failure("examples/set.er", 1)
-}
-
-#[test]
-fn exec_side_effect() -> Result<(), ()> {
-    expect_failure("examples/side_effect.er", 4)
-}
-
-#[test]
-fn exec_subtyping() -> Result<(), ()> {
-    expect_failure("tests/subtyping.er", 1)
-}
-
 #[test]
 fn exec_trait() -> Result<(), ()> {
     expect_success("examples/trait.er")
@@ -154,6 +119,51 @@ fn exec_with() -> Result<(), ()> {
     expect_success("examples/with.er")
 }
 
+#[test]
+fn exec_addition_err() -> Result<(), ()> {
+    expect_failure("tests/should_err/addition.er", 1)
+}
+
+#[test]
+fn exec_invalid_param() -> Result<(), ()> {
+    expect_failure("tests/should_err/invalid_param.er", 3)
+}
+
+#[test]
+fn exec_move_check() -> Result<(), ()> {
+    expect_failure("examples/move_check.er", 1)
+}
+
+#[test]
+fn exec_pyimport() -> Result<(), ()> {
+    if cfg!(unix) {
+        expect_end_with("examples/pyimport.er", 111)
+    } else {
+        expect_failure("examples/pyimport.er", 1)
+    }
+}
+
+#[test]
+fn exec_rec() -> Result<(), ()> {
+    // this script is valid but the current code generating process has a bug.
+    expect_end_with("tests/should_err/rec.er", 1)
+}
+
+#[test]
+fn exec_set() -> Result<(), ()> {
+    expect_failure("examples/set.er", 1)
+}
+
+#[test]
+fn exec_side_effect() -> Result<(), ()> {
+    expect_failure("examples/side_effect.er", 4)
+}
+
+#[test]
+fn exec_subtyping() -> Result<(), ()> {
+    expect_failure("tests/should_err/subtyping.er", 1)
+}
+
 fn expect_success(file_path: &'static str) -> Result<(), ()> {
     match exec_vm(file_path) {
         Ok(0) => Ok(()),