ref: 82b07338710f9c928e7cddfd2554ee62a4eb2e39
parent: 11a32d05eefc1d6cabd5312af46eba9b793174fd
author: Lennart Augustsson <lennart@augustsson.net>
date: Tue Dec 26 04:41:14 EST 2023
Complain about extra bindings in instances
--- a/README.md
+++ b/README.md
@@ -2,6 +2,8 @@
This directory contains an implementation of a small subset of Haskell.
It uses combinators for the runtime execution.
+The runtime system has minimal dependencies, and can be compiled even for micro-controllers.
+
The compiler can compile itself.
## Compiling MicroHs
@@ -28,12 +30,11 @@
Differences:
* Top level definitions must have a type signature.
* Type variables need an explicit `forall`.
- * Type variables without a kind annotation are assumed to have kind `Type`.
* There is no `Read` class.
* There is no deriving.
- * There is no record syntax.
+ * Indentation is handled a little differently.
* The `Prelude` has to be imported explicitly.
- * Polymorphic types are never inferred; use a type signature if you need it.
+ * Polymorphic types/kinds are never inferred; use a type/kind signature if you need it.
* A module must have an export list.
* The `default` list is empty, except in the interactive system.
* Always enabled extension:
--- a/src/MicroHs/TCMonad.hs
+++ b/src/MicroHs/TCMonad.hs
@@ -150,11 +150,11 @@
uvarSubst :: (IM.IntMap EType), -- mapping from unique id to type
tcMode :: TCMode, -- pattern, value, or type
classTable :: ClassTable, -- class info, indexed by QIdent
- ctxTables :: (InstTable, -- instances
- MetaTable, -- instances with unification variables
+ ctxTables :: (InstTable, -- instances
+ MetaTable, -- instances with unification variables
TypeEqTable), -- type equalities
constraints :: Constraints, -- constraints that have to be solved
- defaults :: Defaults -- current defaults
+ defaults :: Defaults -- current defaults
}
typeTable :: TCState -> TypeTable
--- a/src/MicroHs/TypeCheck.hs
+++ b/src/MicroHs/TypeCheck.hs
@@ -1186,6 +1186,9 @@
meths = map meth mis
sups = map (const (EVar $ mkIdentSLoc loc dictPrefixDollar)) supers
args = sups ++ meths
+ case map fst ies \\ mis of
+ [] -> return ()
+ i:_ -> tcError (getSLoc i) $ "superflous binding " ++ show i
let bind = Fcn iInst $ eEqns [] $ foldl EApp (EVar $ mkClassConstructor qiCls) args
mn <- gets moduleName
addInstTable [(EVar $ qualIdent mn iInst, vks, ctx, cc, fds)]
--- a/tests/errmsg.test
+++ b/tests/errmsg.test
@@ -157,4 +157,12 @@
mhs: "../tmp/E.hs": line 6, col 11: existentials not allowed in pattern binding
=====
+module E() where
+import Prelude
+class C a where { m :: a }+instance C Int where { x = 1 }+-----
+mhs: "../tmp/E.hs": line 5, col 24: superflous binding x
+
+=====
END
--
⑨