some fixes:

- always remove imports from definition modules
- minor improvement in error messages

lang/m2/comp/chk_expr.c

@@ -53,6 +53,15 @@ df_error(nd, mess, edf)
 	return 0;
 }
 
+STATIC int
+ex_error(nd, mess)
+	t_node	*nd;
+	char	*mess;
+{
+	node_error(nd, "\"%s\": %s", symbol2str(nd->nd_symb), mess);
+	return 0;
+}
+
 MkCoercion(pnd, tp)
 	t_node		**pnd;
 	register t_type	*tp;
@@ -160,8 +169,7 @@ ChkArrow(expp)
 	tp = expp->nd_right->nd_type;
 
 	if (tp->tp_fund != T_POINTER) {
-		node_error(expp, "\"^\": illegal operand");
+		return ex_error(expp, "illegal operand type");
-		return 0;
 	}
 
 	expp->nd_type = RemoveEqual(PointedtoType(tp));
@@ -837,8 +845,7 @@ ChkBinOper(expp)
 	*/
 	if (expp->nd_symb == IN) {
 		if (tpr->tp_fund != T_SET) {
-			node_error(expp, "\"IN\": right operand must be a set");
+			return ex_error(expp, "right operand must be a set");
-			return 0;
 		}
 		if (!TstAssCompat(ElementType(tpr), tpl)) {
 			/* Assignment compatible ???
@@ -863,9 +870,7 @@ ChkBinOper(expp)
 	if (!(tpr->tp_fund & allowed) || !(tpl->tp_fund & allowed)) {
 	    	if (!((T_CARDINAL & allowed) &&
 	             ChkAddress(tpl, tpr))) {
-			node_error(expp, "\"%s\": illegal operand type(s)", 
+			return ex_error(expp, "illegal operand type(s)");
-				     symbol2str(expp->nd_symb));
-			return 0;
 		}
 		if (expp->nd_type->tp_fund & T_CARDINAL) {
 			expp->nd_type = address_type;
@@ -873,17 +878,13 @@ ChkBinOper(expp)
 	}
 
 	if (Boolean(expp->nd_symb) && tpl != bool_type) {
-		node_error(expp, "\"%s\": illegal operand type(s)",
+		return ex_error(expp, "illegal operand type(s)");
-			     symbol2str(expp->nd_symb));
-		return 0;
 	}
 
 	/* Operands must be compatible (distilled from Def 8.2)
 	*/
 	if (!TstCompat(tpr, tpl)) {
-		node_error(expp,"\"%s\": incompatible types",
+		return ex_error(expp, "incompatible operand types");
-			   symbol2str(expp->nd_symb));
-		return 0;
 	}
 
 	MkCoercion(&(expp->nd_left), tpl);
@@ -968,8 +969,7 @@ ChkUnOper(expp)
 	default:
 		crash("ChkUnOper");
 	}
-	node_error(expp, "\"%s\": illegal operand", symbol2str(expp->nd_symb));
+	return ex_error(expp, "illegal operand type");
-	return 0;
 }
 
 STATIC t_node *

lang/m2/comp/def.c

@@ -25,6 +25,7 @@
 #include	"scope.h"
 #include	"node.h"
 #include	"Lpars.h"
+#include	"warning.h"
 
 STATIC
 DefInFront(df)
@@ -185,22 +186,27 @@ define(id, scope, kind)
 	return MkDef(id, scope, kind);
 }
 
-RemoveImports(pdf)
+end_definition_list(pdf)
 	register t_def **pdf;
 {
 	/*	Remove all imports from a definition module. This is
 		neccesary because the implementation module might import
 		them again.
+		Also, mark all other definitions "QUALIFIED EXPORT".
 	*/
 	register t_def *df = *pdf;
 
 	while (df) {
 		if (df->df_kind & D_IMPORTED) {
+			if (! (df->df_flags & D_USED)) {
+				warning(W_ORDINARY, "identifier \"%s\" imported but not used", df->df_idf->id_text);
+			}
 			RemoveFromIdList(df);
 			*pdf = df->df_nextinscope;
 			free_def(df);
 		}
 		else {
+			df->df_flags |= D_QEXPORTED;
 			pdf = &(df->df_nextinscope);
 		}
 		df = *pdf;

lang/m2/comp/program.g

@@ -167,12 +167,7 @@ node_warning(exportlist, W_OLDFASHIONED, "export list in definition module ignor
 		/* empty */
 	]
 	definition* END IDENT
-			{ register t_def *df1 = CurrentScope->sc_def;
+			{ end_definition_list(&(CurrentScope->sc_def));
-			  while (df1) {
-				/* Make all definitions "QUALIFIED EXPORT" */
-				df1->df_flags |= D_QEXPORTED;
-				df1 = df1->df_nextinscope;
-			  }
 			  DefinitionModule--;
 			  match_id(df->df_idf, dot.TOK_IDF);
 			  df->df_flags &= ~D_BUSY;
@@ -219,7 +214,6 @@ ProgramModule
 	IDENT	{ if (state == IMPLEMENTATION) {
 			df = GetDefinitionModule(dot.TOK_IDF, 0);
 			CurrVis = df->mod_vis;
-			RemoveImports(&(CurrentScope->sc_def));
 		  }
 		  else {
 			Defined = df = define(dot.TOK_IDF, GlobalScope, D_MODULE);