- Improved Lux error messages by ensuring the cursor is always present.

33 files changed, 108 insertions, 100 deletions

diff --git a/luxc/src/lux.clj b/luxc/src/lux.clj
index d17f1640d..a013d2421 100644
--- a/luxc/src/lux.clj
+++ b/luxc/src/lux.clj
@@ -5,7 +5,7 @@
 
 (ns lux
   (:gen-class)
-  (:require [lux.base :as & :refer [|let |do return fail return* fail* |case]]
+  (:require [lux.base :as & :refer [|let |do return return* |case]]
             [lux.compiler.base :as &compiler-base]
             [lux.compiler :as &compiler]
             [lux.repl :as &repl]
diff --git a/luxc/src/lux/analyser.clj b/luxc/src/lux/analyser.clj
index f47bcf914..f28d55e23 100644
--- a/luxc/src/lux/analyser.clj
+++ b/luxc/src/lux/analyser.clj
@@ -7,7 +7,7 @@
   (:require (clojure [template :refer [do-template]])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|let |do return fail return* fail* |case]]
+            (lux [base :as & :refer [|let |do return return* |case]]
                  [reader :as &reader]
                  [parser :as &parser]
                  [type :as &type]
diff --git a/luxc/src/lux/analyser/base.clj b/luxc/src/lux/analyser/base.clj
index ccc7260bc..e5e793c34 100644
--- a/luxc/src/lux/analyser/base.clj
+++ b/luxc/src/lux/analyser/base.clj
@@ -6,7 +6,7 @@
 (ns lux.analyser.base
   (:require clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [defvariant |let |do return* return fail |case]]
+            (lux [base :as & :refer [defvariant |let |do return* return |case]]
                  [type :as &type])))
 
 ;; [Tags]
@@ -60,7 +60,7 @@
       (return x)
 
       _
-      (fail "[Analyser Error] Can't expand to other than 1 element."))))
+      (&/fail-with-loc "[Analyser Error] Can't expand to other than 1 element."))))
 
 (defn analyse-1 [analyse exo-type elem]
   (&/with-expected-type exo-type
diff --git a/luxc/src/lux/analyser/case.clj b/luxc/src/lux/analyser/case.clj
index 042ca8352..8bb5cca35 100644
--- a/luxc/src/lux/analyser/case.clj
+++ b/luxc/src/lux/analyser/case.clj
@@ -6,7 +6,7 @@
 (ns lux.analyser.case
   (:require clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [defvariant |do return fail |let |case]]
+            (lux [base :as & :refer [defvariant |do return |let |case]]
                  [parser :as &parser]
                  [type :as &type])
             (lux.analyser [base :as &&]
@@ -48,7 +48,7 @@
   (|case type
     (&/$VarT ?id)
     (|do [type* (&/try-all% (&/|list (&type/deref ?id)
-                                     (fail "##1##")))]
+                                     (&/fail-with-loc "##1##")))]
       (resolve-type type*))
 
     (&/$UnivQ _)
@@ -185,7 +185,7 @@
       (apply-type! =type-fun param))
     
     _
-    (fail (str "[Type System] Not a type function:\n" (&type/show-type type-fn) "\n"))))
+    (&/fail-with-loc (str "[Type System] Not a type function:\n" (&type/show-type type-fn) "\n"))))
 
 (defn adjust-type* [up type]
   "(-> (List (, (Maybe (List Type)) Int Type)) Type (Lux Type))"
@@ -240,7 +240,7 @@
 
     (&/$VarT ?id)
     (|do [type* (&/try-all% (&/|list (&type/deref ?id)
-                                     (fail (str "##2##: " ?id))))]
+                                     (&/fail-with-loc (str "##2##: " ?id))))]
       (adjust-type* up type*))
 
     (&/$NamedT ?name ?type)
@@ -250,7 +250,7 @@
     (return type)
 
     _
-    (fail (str "[Pattern-matching Error] Can't adjust type: " (&type/show-type type)))
+    (&/fail-with-loc (str "[Pattern-matching Error] Can't adjust type: " (&type/show-type type)))
     ))
 
 (defn adjust-type [type]
@@ -274,7 +274,7 @@
           (return (&/T [($StoreTestAC idx) =kont]))))
       
       (&/$SymbolS ident)
-      (fail (str "[Pattern-matching Error] Symbols must be unqualified: " (&/ident->text ident)))
+      (&/fail-with-loc (str "[Pattern-matching Error] Symbols must be unqualified: " (&/ident->text ident)))
 
       (&/$BoolS ?value)
       (|do [_ (&type/check value-type &type/Bool)
@@ -340,12 +340,12 @@
                                                (return (&/T [&/$Nil =kont])))
                                              (&/|reverse (&/zip2 _tuple-types ?members)))]
                   (return (&/T [($TupleTestAC =tests) =kont])))
-                (fail (str "[Pattern-matching Error] Pattern-matching mismatch. Require tuple[" (&/|length (&type/flatten-prod value-type*)) "]. Given tuple [" (&/|length ?members) "]"
-                           " -- " (&/show-ast pattern)
-                           " " (&type/show-type value-type*) " " (&type/show-type value-type)))))
+                (&/fail-with-loc (str "[Pattern-matching Error] Pattern-matching mismatch. Require tuple[" (&/|length (&type/flatten-prod value-type*)) "]. Given tuple [" (&/|length ?members) "]"
+                                      " -- " (&/show-ast pattern)
+                                      " " (&type/show-type value-type*) " " (&type/show-type value-type)))))
 
             _
-            (fail (str "[Pattern-matching Error] Tuples require tuple-types: " (&type/show-type value-type))))))
+            (&/fail-with-loc (str "[Pattern-matching Error] Tuples require tuple-types: " (&type/show-type value-type))))))
 
       (&/$RecordS pairs)
       (|do [[rec-members rec-type] (&&record/order-record pairs)
@@ -403,7 +403,7 @@
         (return (&/T [($VariantTestAC (&/T [idx (&/|length group) =test])) =kont])))
 
       _
-      (fail (str "[Pattern-matching Error] Unrecognized pattern syntax: " (&/show-ast pattern)))
+      (&/fail-with-loc (str "[Pattern-matching Error] Unrecognized pattern syntax: " (&/show-ast pattern)))
       )))
 
 (defn ^:private analyse-branch [analyse exo-type var?? value-type pattern body patterns]
@@ -528,7 +528,7 @@
                                  (merge-total v (&/T [t ?body])))
                                ?values ?tests)]
           (return ($TupleTotal total? structs)))
-        (fail "[Pattern-matching Error] Inconsistent tuple-size."))
+        (&/fail-with-loc "[Pattern-matching Error] Inconsistent tuple-size."))
 
       [($DefaultTotal total?) ($VariantTestAC ?tag ?count ?test)]
       (|do [sub-struct (merge-total ($DefaultTotal total?)
@@ -538,7 +538,7 @@
                       (return list)
 
                       (&/$None)
-                      (fail "[Pattern-matching Error] YOLO"))]
+                      (&/fail-with-loc "[Pattern-matching Error] YOLO"))]
         (return ($VariantTotal total? structs)))
 
       [($VariantTotal total? ?branches) ($VariantTestAC ?tag ?count ?test)]
@@ -554,7 +554,7 @@
                       (return list)
 
                       (&/$None)
-                      (fail "[Pattern-matching Error] YOLO"))]
+                      (&/fail-with-loc "[Pattern-matching Error] YOLO"))]
         (return ($VariantTotal total? structs)))
       )))
 
@@ -610,7 +610,7 @@
           (return true)
 
           _
-          (fail "[Pattern-maching Error] Unit is not total.")))
+          (&/fail-with-loc "[Pattern-maching Error] Unit is not total.")))
       
       _
       (|do [unknown? (&type/unknown? value-type)]
@@ -632,10 +632,10 @@
                   (if (= num-elems _shorter)
                     (|do [totals (&/map2% check-totality _tuple-types ?structs)]
                       (return (&/fold #(and %1 %2) true totals)))
-                    (fail (str "[Pattern-maching Error] Tuple-mismatch. Require tuple[" (&/|length (&type/flatten-prod value-type*)) "]. Given tuple [" (&/|length ?structs) "]"))))
+                    (&/fail-with-loc (str "[Pattern-maching Error] Tuple-mismatch. Require tuple[" (&/|length (&type/flatten-prod value-type*)) "]. Given tuple [" (&/|length ?structs) "]"))))
                 
                 _
-                (fail (str "[Pattern-maching Error] Tuple is not total." " - " (&type/show-type value-type*)))))))))
+                (&/fail-with-loc (str "[Pattern-maching Error] Tuple is not total." " - " (&type/show-type value-type*)))))))))
 
     ($VariantTotal ?total ?structs)
     (if ?total
@@ -649,7 +649,7 @@
             (return (&/fold #(and %1 %2) true totals)))
 
           _
-          (fail "[Pattern-maching Error] Variant is not total."))))
+          (&/fail-with-loc "[Pattern-maching Error] Variant is not total."))))
     ))
 
 ;; [Exports]
@@ -663,4 +663,4 @@
         ? (check-totality value-type struct)]
     (if ?
       (return patterns)
-      (fail "[Pattern-maching Error] Pattern-matching is non-total."))))
+      (&/fail-with-loc "[Pattern-maching Error] Pattern-matching is non-total."))))
diff --git a/luxc/src/lux/analyser/env.clj b/luxc/src/lux/analyser/env.clj
index 75e066e34..5c0133821 100644
--- a/luxc/src/lux/analyser/env.clj
+++ b/luxc/src/lux/analyser/env.clj
@@ -6,7 +6,7 @@
 (ns lux.analyser.env
   (:require clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|do return return* fail fail* |case]])
+            (lux [base :as & :refer [|do return return* |case]])
             [lux.analyser.base :as &&]))
 
 ;; [Exports]
@@ -67,7 +67,8 @@
   (fn [state]
     (|case (&/get$ &/$scopes state)
       (&/$Nil)
-      (fail* "[Analyser Error] Can't obtain captured vars without environments.")
+      ((&/fail-with-loc "[Analyser Error] Can't obtain captured vars without environments.")
+       state)
 
       (&/$Cons env _)
       (return* state (->> env (&/get$ &/$closure) (&/get$ &/$mappings))))
diff --git a/luxc/src/lux/analyser/lambda.clj b/luxc/src/lux/analyser/lambda.clj
index b47b803d0..b460a2e18 100644
--- a/luxc/src/lux/analyser/lambda.clj
+++ b/luxc/src/lux/analyser/lambda.clj
@@ -6,7 +6,7 @@
 (ns lux.analyser.lambda
   (:require clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|let |do return fail |case]]
+            (lux [base :as & :refer [|let |do return |case]]
                  [host :as &host])
             (lux.analyser [base :as &&]
                           [env :as &env])))
diff --git a/luxc/src/lux/analyser/lux.clj b/luxc/src/lux/analyser/lux.clj
index 7ca31f322..2d439dd03 100644
--- a/luxc/src/lux/analyser/lux.clj
+++ b/luxc/src/lux/analyser/lux.clj
@@ -8,7 +8,7 @@
                      [set :as set])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|do return return* fail fail* |let |list |case]]
+            (lux [base :as & :refer [|do return return* |let |list |case]]
                  [parser :as &parser]
                  [type :as &type]
                  [host :as &host])
@@ -298,8 +298,10 @@
                          state)
 
             _
-            (fail* "[Analyser Error] Can't have anything other than a global def in the global environment."))
-          (fail* (str "[Analyser Error] Unknown global definition: " name)))
+            ((&/fail-with-loc "[Analyser Error] Can't have anything other than a global def in the global environment.")
+             state))
+          ((&/fail-with-loc (str "[Analyser Error] Unknown global definition: " name))
+           state))
         
         (&/$Cons bottom-outer _)
         (|let [scopes (&/|map #(&/get$ &/$name %) (&/|reverse inner))
@@ -524,7 +526,7 @@
                               (&&/$lambda register-offset =scope =captured =body))))
 
           _
-          (fail "")))
+          (&/fail "")))
       (fn [err]
         (&/fail-with-loc (str err "\n" "[Analyser Error] Functions require function types: " (&type/show-type exo-type)))))
     ))
@@ -675,7 +677,7 @@
                        (set-compiler (merge-compilers current-module _new-compiler compiler))
 
                        (&/$Left ?error)
-                       (fail ?error)))
+                       (&/fail ?error)))
                    _compiler
                    =asyncs)]
     (return &/$Nil)))
diff --git a/luxc/src/lux/analyser/meta.clj b/luxc/src/lux/analyser/meta.clj
index 20bbaef68..931558374 100644
--- a/luxc/src/lux/analyser/meta.clj
+++ b/luxc/src/lux/analyser/meta.clj
@@ -7,7 +7,7 @@
   (:require (clojure [template :refer [do-template]])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|let |do return return* fail fail* |case]])))
+            (lux [base :as & :refer [|let |do return return* |case]])))
 
 ;; [Utils]
 (defn ^:private ident= [x y]
diff --git a/luxc/src/lux/analyser/parser.clj b/luxc/src/lux/analyser/parser.clj
index 586806942..b52abacee 100644
--- a/luxc/src/lux/analyser/parser.clj
+++ b/luxc/src/lux/analyser/parser.clj
@@ -7,7 +7,7 @@
   (:require (clojure [template :refer [do-template]])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|do return* return fail fail* |let |case]]
+            (lux [base :as & :refer [|do return* return |let |case]]
                  [reader :as &reader]
                  [lexer :as &lexer]
                  [parser :as &parser])))
diff --git a/luxc/src/lux/analyser/record.clj b/luxc/src/lux/analyser/record.clj
index 81332b34c..4b3e9243d 100644
--- a/luxc/src/lux/analyser/record.clj
+++ b/luxc/src/lux/analyser/record.clj
@@ -6,7 +6,7 @@
 (ns lux.analyser.record
   (:require clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|let |do return fail |case]]
+            (lux [base :as & :refer [|let |do return |case]]
                  [type :as &type])
             (lux.analyser [base :as &&]
                           [module :as &&module])))
diff --git a/luxc/src/lux/base.clj b/luxc/src/lux/base.clj
index f893f3a02..f47677852 100644
--- a/luxc/src/lux/base.clj
+++ b/luxc/src/lux/base.clj
@@ -667,7 +667,7 @@
       ((exhaust% step) state*)
 
       ($Left msg)
-      (if (.equals "[Reader Error] EOF" msg)
+      (if (.contains msg "[Reader Error] EOF")
         (return* state unit-tag)
         (fail* msg)))))
 
diff --git a/luxc/src/lux/compiler.clj b/luxc/src/lux/compiler.clj
index 0c30c76e9..91dde8898 100644
--- a/luxc/src/lux/compiler.clj
+++ b/luxc/src/lux/compiler.clj
@@ -10,7 +10,7 @@
                      [template :refer [do-template]])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|let |do return* return fail fail* |case]]
+            (lux [base :as & :refer [|let |do return* return |case]]
                  [type :as &type]
                  [reader :as &reader]
                  [lexer :as &lexer]
@@ -186,7 +186,7 @@
                     (let [compiler-step (&analyser/analyse &optimizer/optimize eval! compile-module!! all-compilers)]
                       (|do [module-exists? (&a-module/exists? name)]
                         (if module-exists?
-                          (fail "[Compiler Error] Can't redefine a module!")
+                          (&/fail-with-loc "[Compiler Error] Can't redefine a module!")
                           (|do [_ (&&cache/delete name)
                                 _ (&a-module/create-module name file-hash)
                                 _ (&/flag-active-module name)
@@ -250,7 +250,7 @@
                                              ?state)
                                 
                                 (&/$Left ?message)
-                                (fail* ?message))))))))
+                                (&/fail* ?message))))))))
         )
       )))
 
diff --git a/luxc/src/lux/compiler/base.clj b/luxc/src/lux/compiler/base.clj
index 1e508f6ea..9a990d9fc 100644
--- a/luxc/src/lux/compiler/base.clj
+++ b/luxc/src/lux/compiler/base.clj
@@ -9,7 +9,7 @@
             [clojure.java.io :as io]
             [clojure.core.match :as M :refer [matchv]]
             clojure.core.match.array
-            (lux [base :as & :refer [|let |do return* return fail fail*]]
+            (lux [base :as & :refer [|let |do return* return fail*]]
                  [type :as &type]
                  [host :as &host])
             (lux.analyser [base :as &a]
diff --git a/luxc/src/lux/compiler/cache.clj b/luxc/src/lux/compiler/cache.clj
index 436f778f5..3d09a9c88 100644
--- a/luxc/src/lux/compiler/cache.clj
+++ b/luxc/src/lux/compiler/cache.clj
@@ -9,7 +9,7 @@
             [clojure.java.io :as io]
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|do return* return fail fail* |case |let]]
+            (lux [base :as & :refer [|do return* return |case |let]]
                  [type :as &type]
                  [host :as &host])
             [lux.host.generics :as &host-generics]
@@ -276,4 +276,4 @@
     (|do [_ (inject-module module-name module-struct)
           _ (&/flag-cached-module module-name)]
       (return nil))
-    (fail (str "[Cache Error] Module is not cached: " module-name))))
+    (&/fail (str "[Cache Error] Module is not cached: " module-name))))
diff --git a/luxc/src/lux/compiler/cache/ann.clj b/luxc/src/lux/compiler/cache/ann.clj
index e2df55286..a4dbb1605 100644
--- a/luxc/src/lux/compiler/cache/ann.clj
+++ b/luxc/src/lux/compiler/cache/ann.clj
@@ -8,7 +8,7 @@
                      [string :as string])
             [clojure.core.match :as M :refer [matchv]]
             clojure.core.match.array
-            (lux [base :as & :refer [|let |do return* return fail fail* |case]])))
+            (lux [base :as & :refer [|let |do return* return |case]])))
 
 (def ^:private stop (->> 7 char str))
 (def ^:private cons-signal (->> 5 char str))
diff --git a/luxc/src/lux/compiler/cache/type.clj b/luxc/src/lux/compiler/cache/type.clj
index eb82e162f..18440b6fc 100644
--- a/luxc/src/lux/compiler/cache/type.clj
+++ b/luxc/src/lux/compiler/cache/type.clj
@@ -8,7 +8,7 @@
                      [string :as string])
             [clojure.core.match :as M :refer [matchv]]
             clojure.core.match.array
-            (lux [base :as & :refer [|let |do return* return fail fail* |case]]
+            (lux [base :as & :refer [|let |do return* return |case]]
                  [type :as &type])))
 
 (def ^:private stop (->> 7 char str))
diff --git a/luxc/src/lux/compiler/case.clj b/luxc/src/lux/compiler/case.clj
index 416c93622..1bc87ff9b 100644
--- a/luxc/src/lux/compiler/case.clj
+++ b/luxc/src/lux/compiler/case.clj
@@ -8,7 +8,7 @@
                      [template :refer [do-template]])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|do return* return fail fail* |let |case]]
+            (lux [base :as & :refer [|do return* return |let |case]]
                  [type :as &type]
                  [lexer :as &lexer]
                  [parser :as &parser]
diff --git a/luxc/src/lux/compiler/host.clj b/luxc/src/lux/compiler/host.clj
index 10a718093..5b8703a51 100644
--- a/luxc/src/lux/compiler/host.clj
+++ b/luxc/src/lux/compiler/host.clj
@@ -9,7 +9,7 @@
                      [template :refer [do-template]])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|do return* return fail fail* |let |case]]
+            (lux [base :as & :refer [|do return* return |let |case]]
                  [type :as &type]
                  [lexer :as &lexer]
                  [parser :as &parser]
@@ -2807,7 +2807,7 @@
       "s2l"             (compile-jvm-s2l compile ?values special-args)
       "b2l"             (compile-jvm-b2l compile ?values special-args)
       ;; else
-      (fail (str "[Compiler Error] Unknown host procedure: " [proc-category proc-name])))
+      (&/fail-with-loc (str "[Compiler Error] Unknown host procedure: " [proc-category proc-name])))
 
     ;; else
-    (fail (str "[Compiler Error] Unknown host procedure: " [proc-category proc-name]))))
+    (&/fail-with-loc (str "[Compiler Error] Unknown host procedure: " [proc-category proc-name]))))
diff --git a/luxc/src/lux/compiler/io.clj b/luxc/src/lux/compiler/io.clj
index aea1c352d..6e5aced34 100644
--- a/luxc/src/lux/compiler/io.clj
+++ b/luxc/src/lux/compiler/io.clj
@@ -4,7 +4,7 @@
 ;;  You can obtain one at http://mozilla.org/MPL/2.0/.
 
 (ns lux.compiler.io
-  (:require (lux [base :as & :refer [|case |let |do return* return fail fail*]])
+  (:require (lux [base :as & :refer [|case |let |do return* return fail*]])
             (lux.compiler [base :as &&])
             [lux.lib.loader :as &lib]))
 
diff --git a/luxc/src/lux/compiler/lambda.clj b/luxc/src/lux/compiler/lambda.clj
index c0096523f..82e4979bb 100644
--- a/luxc/src/lux/compiler/lambda.clj
+++ b/luxc/src/lux/compiler/lambda.clj
@@ -9,7 +9,7 @@
                      [template :refer [do-template]])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|do return* return fail fail* |case |let]]
+            (lux [base :as & :refer [|do return* return |case |let]]
                  [type :as &type]
                  [lexer :as &lexer]
                  [parser :as &parser]
diff --git a/luxc/src/lux/compiler/lux.clj b/luxc/src/lux/compiler/lux.clj
index fd4130707..222c40a9d 100644
--- a/luxc/src/lux/compiler/lux.clj
+++ b/luxc/src/lux/compiler/lux.clj
@@ -9,7 +9,7 @@
                      [template :refer [do-template]])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|do return* return fail fail* |let |case]]
+            (lux [base :as & :refer [|do return* return |let |case]]
                  [type :as &type]
                  [lexer :as &lexer]
                  [parser :as &parser]
@@ -270,10 +270,10 @@
                 _ (&/without-repl-closure
                    (&a-module/define module-name ?name def-type def-meta def-value))]
             (return nil))
-          (fail (str "[Compilation Error] Aliases cannot contain meta-data: " module-name ";" ?name)))
+          (&/fail-with-loc (str "[Compilation Error] Aliases cannot contain meta-data: " module-name ";" ?name)))
 
         (&/$Some _)
-        (fail "[Compilation Error] Invalid syntax for lux;alias meta-data. Must be an Ident.")
+        (&/fail-with-loc "[Compilation Error] Invalid syntax for lux;alias meta-data. Must be an Ident.")
         
         _
         (|case (de-ann ?body)
@@ -336,16 +336,16 @@
                                              (return tag)
 
                                              _
-                                             (fail "[Compiler Error] Incorrect format for tags.")))
+                                             (&/fail-with-loc "[Compiler Error] Incorrect format for tags.")))
                                          tags*)
                             _ (&a-module/declare-tags module-name tags was-exported? def-value)]
                         (return nil))
 
                       [false (&/$Some _)]
-                      (fail "[Compiler Error] Can't define tags for non-type.")
+                      (&/fail-with-loc "[Compiler Error] Can't define tags for non-type.")
 
                       [true (&/$Some _)]
-                      (fail "[Compiler Error] Incorrect format for tags.")
+                      (&/fail-with-loc "[Compiler Error] Incorrect format for tags.")
 
                       [_ (&/$None)]
                       (return nil))
@@ -407,16 +407,16 @@
                                            (return tag)
 
                                            _
-                                           (fail "[Compiler Error] Incorrect format for tags.")))
+                                           (&/fail-with-loc "[Compiler Error] Incorrect format for tags.")))
                                        tags*)
                           _ (&a-module/declare-tags module-name tags was-exported? def-value)]
                       (return nil))
 
                     [false (&/$Some _)]
-                    (fail "[Compiler Error] Can't define tags for non-type.")
+                    (&/fail-with-loc "[Compiler Error] Can't define tags for non-type.")
 
                     [true (&/$Some _)]
-                    (fail "[Compiler Error] Incorrect format for tags.")
+                    (&/fail-with-loc "[Compiler Error] Incorrect format for tags.")
 
                     [_ (&/$None)]
                     (return nil))
diff --git a/luxc/src/lux/compiler/module.clj b/luxc/src/lux/compiler/module.clj
index 03bc311f2..445876e1f 100644
--- a/luxc/src/lux/compiler/module.clj
+++ b/luxc/src/lux/compiler/module.clj
@@ -9,7 +9,7 @@
                      [template :refer [do-template]])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|let |do return* return fail fail* |case]]
+            (lux [base :as & :refer [|let |do return* return |case]]
                  [type :as &type])
             [lux.analyser.module :as &module]))
 
diff --git a/luxc/src/lux/compiler/parallel.clj b/luxc/src/lux/compiler/parallel.clj
index 8f6fee99d..08f780a90 100644
--- a/luxc/src/lux/compiler/parallel.clj
+++ b/luxc/src/lux/compiler/parallel.clj
@@ -9,7 +9,7 @@
                      [template :refer [do-template]])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|let |do return* return fail fail* |case]])))
+            (lux [base :as & :refer [|let |do return* return |case]])))
 
 ;; [Utils]
 (def ^:private !state! (ref {}))
diff --git a/luxc/src/lux/host.clj b/luxc/src/lux/host.clj
index 39e659964..5a9fade72 100644
--- a/luxc/src/lux/host.clj
+++ b/luxc/src/lux/host.clj
@@ -8,7 +8,7 @@
                      [template :refer [do-template]])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|do return* return fail fail* |let |case]]
+            (lux [base :as & :refer [|do return* return |let |case]]
                  [type :as &type])
             [lux.type.host :as &host-type]
             [lux.host.generics :as &host-generics])
diff --git a/luxc/src/lux/host/generics.clj b/luxc/src/lux/host/generics.clj
index cfd0d2d54..70912f9d0 100644
--- a/luxc/src/lux/host/generics.clj
+++ b/luxc/src/lux/host/generics.clj
@@ -8,7 +8,7 @@
                      [template :refer [do-template]])
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|do return* return fail fail* |let |case]]))
+            (lux [base :as & :refer [|do return* return |let |case]]))
   (:import java.util.regex.Pattern))
 
 (declare gclass->signature)
diff --git a/luxc/src/lux/lexer.clj b/luxc/src/lux/lexer.clj
index 9dc77b411..579fc3fad 100644
--- a/luxc/src/lux/lexer.clj
+++ b/luxc/src/lux/lexer.clj
@@ -6,7 +6,7 @@
 (ns lux.lexer
   (:require (clojure [template :refer [do-template]]
                      [string :as string])
-            (lux [base :as & :refer [defvariant |do return* return fail fail* |case]]
+            (lux [base :as & :refer [defvariant |do return* return |case]]
                  [reader :as &reader])
             [lux.analyser.module :as &module]))
 
diff --git a/luxc/src/lux/lib/loader.clj b/luxc/src/lux/lib/loader.clj
index e8310f9f0..1e160746d 100644
--- a/luxc/src/lux/lib/loader.clj
+++ b/luxc/src/lux/lib/loader.clj
@@ -5,7 +5,7 @@
 
 (ns lux.lib.loader
   (:refer-clojure :exclude [load])
-  (:require (lux [base :as & :refer [|let |do return fail return* fail* |case]]))
+  (:require (lux [base :as & :refer [|let |do return return* |case]]))
   (:import (java.io InputStream
                     File
                     FileInputStream
diff --git a/luxc/src/lux/optimizer.clj b/luxc/src/lux/optimizer.clj
index 8ce8fc20e..88d0a68b3 100644
--- a/luxc/src/lux/optimizer.clj
+++ b/luxc/src/lux/optimizer.clj
@@ -3,7 +3,7 @@
 ;;  If a copy of the MPL was not distributed with this file,
 ;;  You can obtain one at http://mozilla.org/MPL/2.0/.
 (ns lux.optimizer
-  (:require (lux [base :as & :refer [|let |do return fail return* fail* |case defvariant]])
+  (:require (lux [base :as & :refer [|let |do return return* |case defvariant]])
             (lux.analyser [base :as &a]
                           [case :as &a-case])))
 
diff --git a/luxc/src/lux/parser.clj b/luxc/src/lux/parser.clj
index c32528096..1b56cf213 100644
--- a/luxc/src/lux/parser.clj
+++ b/luxc/src/lux/parser.clj
@@ -18,14 +18,10 @@
   (fn [state]
     (|case (action state)
       (&/$Left ^String error)
-      (cond (.contains error base-uneven-record-error)
-            (&/$Left error)
-
-            (not (.contains error "[Parser Error]"))
-            (&/$Left error)
-
-            :else
-            (&/$Right (&/T [state &/$Nil])))
+      (if (or (.contains error base-uneven-record-error)
+              (not (.contains error "[Parser Error]")))
+        (&/$Left error)
+        (&/$Right (&/T [state &/$Nil])))
 
       (&/$Right state* head)
       ((|do [tail (repeat% action)]
diff --git a/luxc/src/lux/reader.clj b/luxc/src/lux/reader.clj
index 5a7734061..43875ed95 100644
--- a/luxc/src/lux/reader.clj
+++ b/luxc/src/lux/reader.clj
@@ -7,7 +7,7 @@
   (:require [clojure.string :as string]
             clojure.core.match
             clojure.core.match.array
-            [lux.base :as & :refer [defvariant |do return* return fail* |let |case]]))
+            [lux.base :as & :refer [defvariant |do return* return |let |case]]))
 
 ;; [Tags]
 (defvariant
@@ -20,8 +20,8 @@
   (fn [state]
     (|case (&/get$ &/$source state)
       (&/$Nil)
-      (fail* "[Reader Error] EOF")
-
+      ((&/fail-with-loc "[Reader Error] EOF") state)
+      
       (&/$Cons [[file-name line-num column-num] line]
                more)
       (|case (body file-name line-num column-num line)
@@ -135,7 +135,7 @@
     (|let [old-source (&/get$ &/$source state)]
       (|case (body (&/set$ &/$source (from name content) state))
         (&/$Left error)
-        (&/$Left error)
+        ((&/fail-with-loc error) state)
 
         (&/$Right state* output)
         (&/$Right (&/T [(&/set$ &/$source old-source state*) output]))))))
diff --git a/luxc/src/lux/repl.clj b/luxc/src/lux/repl.clj
index 1c727f246..28f820693 100644
--- a/luxc/src/lux/repl.clj
+++ b/luxc/src/lux/repl.clj
@@ -6,7 +6,7 @@
 (ns lux.repl
   (:require clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|let |do return* return fail fail* |case]]
+            (lux [base :as & :refer [|let |do return* return |case]]
                  [type :as &type]
                  [analyser :as &analyser]
                  [optimizer :as &optimizer]
@@ -46,7 +46,9 @@
         ?state)
 
       (&/$Left ?message)
-      (assert false ?message))
+      (do (println (str "Initialization failed:\n" ?message))
+        (flush)
+        (System/exit 1)))
     ))
 
 ;; [Values]
diff --git a/luxc/src/lux/type.clj b/luxc/src/lux/type.clj
index 099682775..6f91cfa01 100644
--- a/luxc/src/lux/type.clj
+++ b/luxc/src/lux/type.clj
@@ -8,7 +8,7 @@
   (:require [clojure.template :refer [do-template]]
             clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|do return* return fail fail* assert! |let |case]])
+            (lux [base :as & :refer [|do return* return assert! |let |case]])
             [lux.type.host :as &&host]))
 
 (declare show-type
@@ -170,7 +170,8 @@
         
         (&/$None)
         (return* state false))
-      (fail* (str "[Type Error] <bound?> Unknown type-var: " id)))))
+      ((&/fail-with-loc (str "[Type Error] <bound?> Unknown type-var: " id))
+       state))))
 
 (defn deref [id]
   (fn [state]
@@ -180,8 +181,10 @@
         (return* state type)
         
         (&/$None)
-        (fail* (str "[Type Error] Unbound type-var: " id)))
-      (fail* (str "[Type Error] <deref> Unknown type-var: " id)))))
+        ((&/fail-with-loc (str "[Type Error] Unbound type-var: " id))
+         state))
+      ((&/fail-with-loc (str "[Type Error] <deref> Unknown type-var: " id))
+       state))))
 
 (defn deref+ [type]
   (|case type
@@ -189,7 +192,7 @@
     (deref id)
 
     _
-    (fail (str "[Type Error] Type is not a variable: " (show-type type)))
+    (&/fail-with-loc (str "[Type Error] Type is not a variable: " (show-type type)))
     ))
 
 (defn set-var [id type]
@@ -199,14 +202,16 @@
         (&/$Some bound)
         (if (type= type bound)
           (return* state nil)
-          (fail* (str "[Type Error] Can't re-bind type var: " id " | Current type: " (show-type bound))))
+          ((&/fail-with-loc (str "[Type Error] Can't re-bind type var: " id " | Current type: " (show-type bound)))
+           state))
         
         (&/$None)
         (return* (&/update$ &/$type-vars (fn [ts] (&/update$ &/$mappings #(&/|put id (&/$Some type) %)
                                                             ts))
                             state)
                  nil))
-      (fail* (str "[Type Error] <set-var> Unknown type-var: " id " | " (->> state (&/get$ &/$type-vars) (&/get$ &/$mappings) &/|length))))))
+      ((&/fail-with-loc (str "[Type Error] <set-var> Unknown type-var: " id " | " (->> state (&/get$ &/$type-vars) (&/get$ &/$mappings) &/|length)))
+       state))))
 
 (defn reset-var [id type]
   (fn [state]
@@ -215,7 +220,8 @@
                                                           ts))
                           state)
                nil)
-      (fail* (str "[Type Error] <set-var> Unknown type-var: " id " | " (->> state (&/get$ &/$type-vars) (&/get$ &/$mappings) &/|length))))))
+      ((&/fail-with-loc (str "[Type Error] <set-var> Unknown type-var: " id " | " (->> state (&/get$ &/$type-vars) (&/get$ &/$mappings) &/|length)))
+       state))))
 
 (defn unset-var [id]
   (fn [state]
@@ -224,7 +230,8 @@
                                                           ts))
                           state)
                nil)
-      (fail* (str "[Type Error] <set-var> Unknown type-var: " id " | " (->> state (&/get$ &/$type-vars) (&/get$ &/$mappings) &/|length))))))
+      ((&/fail-with-loc (str "[Type Error] <set-var> Unknown type-var: " id " | " (->> state (&/get$ &/$type-vars) (&/get$ &/$mappings) &/|length)))
+       state))))
 
 ;; [Exports]
 ;; Type vars
@@ -352,7 +359,7 @@
     (clean* ?id type)
     
     _
-    (fail (str "[Type Error] Not type-var: " (show-type tvar)))))
+    (&/fail-with-loc (str "[Type Error] Not type-var: " (show-type tvar)))))
 
 (defn ^:private unravel-fun [type]
   (|case type
@@ -394,10 +401,10 @@
           [1 (<tag> ?left* _)] (return ?left*)
           [1 _]                (return ?right)
           [_ (<tag> _ _)]      (<at> (dec tag) ?right)
-          _                    (fail (str "[Type Error] " <desc> " lacks member: " tag " | " (show-type type))))
+          _                    (&/fail-with-loc (str "[Type Error] " <desc> " lacks member: " tag " | " (show-type type))))
 
         _
-        (fail (str "[Type Error] Type is not a " <desc> ": " (show-type type))))))
+        (&/fail-with-loc (str "[Type Error] Type is not a " <desc> ": " (show-type type))))))
 
   &/$SumT  flatten-sum  sum-at "Sum"
   &/$ProdT flatten-prod prod-at "Product"
@@ -640,7 +647,7 @@
       (apply-type =type-fun param))
     
     _
-    (fail (str "[Type System] Not a type function:\n" (show-type type-fn) "\n"))))
+    (&/fail-with-loc (str "[Type System] Not a type function:\n" (show-type type-fn) "\n"))))
 
 (def ^:private init-fixpoints &/$Nil)
 
@@ -843,7 +850,7 @@
         (check* class-loader fixpoints invariant?? expected ?atype)
 
         [_ _]
-        (fail ""))
+        (&/fail ""))
       (fn [err]
         (check-error err expected actual)))))
 
@@ -877,7 +884,7 @@
     (return name)
     
     _
-    (fail (str "[Type Error] Type is not named: " (show-type type)))
+    (&/fail-with-loc (str "[Type Error] Type is not named: " (show-type type)))
     ))
 
 (defn unknown? [type]
diff --git a/luxc/src/lux/type/host.clj b/luxc/src/lux/type/host.clj
index 33073fa34..0f2ffde63 100644
--- a/luxc/src/lux/type/host.clj
+++ b/luxc/src/lux/type/host.clj
@@ -6,7 +6,7 @@
 (ns lux.type.host
   (:require clojure.core.match
             clojure.core.match.array
-            (lux [base :as & :refer [|do return* return fail fail* assert! |let |case]])
+            (lux [base :as & :refer [|do return* return assert! |let |case]])
             [lux.host.generics :as &host-generics])
   (:import (java.lang.reflect GenericArrayType
                               ParameterizedType
@@ -119,7 +119,7 @@
         (let [gvar (.getName ^TypeVariable refl-type)]
           (if-let [m-type (&/|get gvar matchings)]
             (return m-type)
-            (fail (str "[Type Error] Unknown generic type variable: " gvar " -- " (->> matchings
+            (&/fail-with-loc (str "[Type Error] Unknown generic type variable: " gvar " -- " (->> matchings
                                                                                        (&/|map &/|first)
                                                                                        &/->seq)))))
         
@@ -180,7 +180,7 @@
     (&/$GenericTypeVar var-name)
     (if-let [m-type (&/|get var-name matchings)]
       (return m-type)
-      (fail (str "[Type Error] Unknown generic type variable: " var-name " -- " (->> matchings
+      (&/fail-with-loc (str "[Type Error] Unknown generic type variable: " var-name " -- " (->> matchings
                                                                                      (&/|map &/|first)
                                                                                      &/->seq))))
     
@@ -236,7 +236,7 @@
       (let [lineage (trace-lineage sub-class+ super-class+)]
         (|do [[^Class sub-class* sub-params*] (raise existential lineage sub-class+ sub-params)]
           (return (&/$HostT (.getName sub-class*) sub-params*))))
-      (fail (str "[Type Error] Classes don't have a subtyping relationship: " sub-class " </= " super-class)))))
+      (&/fail-with-loc (str "[Type Error] Classes don't have a subtyping relationship: " sub-class " </= " super-class)))))
 
 (defn as-obj [class]
   (case class
@@ -284,14 +284,14 @@
                        (if (= (&/|length e!params) (&/|length a!params))
                          (|do [_ (&/map2% check e!params a!params)]
                            (return fixpoints))
-                         (fail (str "[Type Error] Amounts of generic parameters don't match: " e!name "(" (&/|length e!params) ")" " vs " a!name "(" (&/|length a!params) ")")))
+                         (&/fail-with-loc (str "[Type Error] Amounts of generic parameters don't match: " e!name "(" (&/|length e!params) ")" " vs " a!name "(" (&/|length a!params) ")")))
 
                        (not invariant??)
                        (|do [actual* (->super-type existential class-loader e!name a!name a!params)]
                          (check (&/$HostT e!name e!params) actual*))
 
                        :else
-                       (fail (str "[Type Error] Names don't match: " e!name " =/= " a!name)))))
+                       (&/fail-with-loc (str "[Type Error] Names don't match: " e!name " =/= " a!name)))))
       (catch Exception e
         (prn 'check-host-types e [e!name a!name])
         (throw e)))))