From 5b077f5f80cd36fed3b006dd5b0b1cc9025c1b22 Mon Sep 17 00:00:00 2001
From: NeilBrown <neil@brown.name>
Date: Sun, 9 Jun 2019 15:55:21 +1000
Subject: [PATCH] oceani: labels only in 'use' statement.

A variable is only set as a label if it appear at top
level of "use" statement - otherwise it is "unknown".

This makes error messages more meaningful.

Signed-off-by: NeilBrown <neil@brown.name>
---
 csrc/oceani-tests.mdc | 12 +++++-------
 csrc/oceani.mdc       | 17 ++++++++++++++---
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/csrc/oceani-tests.mdc b/csrc/oceani-tests.mdc
index a10d027..5366bf9 100644
--- a/csrc/oceani-tests.mdc
+++ b/csrc/oceani-tests.mdc
@@ -746,7 +746,8 @@ various places that `type_err()` are called.
 	.tmp.code:28:16: error: expected string found Boolean
 	.tmp.code:29:12: error: have number but need string
 	.tmp.code:7:8: info: variable 'c' was set as string here.
-	.tmp.code:32:8: error: field reference attempted on label, not a struct
+	.tmp.code:32:8: error: variable used but not declared: foo
+	.tmp.code:32:8: error: field reference attempted on none, not a struct
 	.tmp.code:32:16: error: expected none found number
 	.tmp.code:33:14: error: field reference attempted on string, not a struct
 	oceani: type error in program - not running.
@@ -757,12 +758,9 @@ various places that `type_err()` are called.
 		print a, b, c
 
 ###### output: type_err4
-	.tmp.code:3:14: error: expected *unknown*type* (labels not permitted) but variable 'b' is label
-	.tmp.code:3:14: info: this is where 'b' was set to label
-	.tmp.code:3:16: error: expected label found number
-	.tmp.code:3:14: info: variable 'b' was set as label here.
-	.tmp.code:4:17: error: expected *unknown*type* (labels not permitted) but variable 'b' is label
-	.tmp.code:3:14: info: this is where 'b' was set to label
+	.tmp.code:3:14: error: variable used but not declared: b
+	.tmp.code:3:16: error: expected none found number
+	.tmp.code:3:14: info: variable 'b' was set as none here.
 	oceani: type error in program - not running.
 
 ###### test list
diff --git a/csrc/oceani.mdc b/csrc/oceani.mdc
index a8653cc..f598344 100644
--- a/csrc/oceani.mdc
+++ b/csrc/oceani.mdc
@@ -1096,7 +1096,7 @@ list of in_scope names.
 
 			v = t->previous;
 			free_value(t->val);
-			if (t->min_depth == 0)
+			if (t->depth == 0)
 				// This is a global constant
 				free_exec(t->where_decl);
 			free(t);
@@ -2344,8 +2344,8 @@ link to find the primary instance.
 			/* This might be a label - allocate a var just in case */
 			v = var_decl(c, $1.txt);
 			if (v) {
-				v->val = val_prepare(Tlabel);
-				v->val.label = &v->val;
+				v->val = val_prepare(Tnone);
+				v->where_decl = $0;
 				v->where_set = $0;
 			}
 		}
@@ -2408,6 +2408,9 @@ link to find the primary instance.
 			         v->where_decl, NULL, 0, NULL);
 			return v->val.type;
 		}
+		if (v->val.type == Tnone && v->where_decl == prog)
+			type_err(c, "error: variable used but not declared: %v",
+			         prog, NULL, 0, NULL);
 		if (v->val.type == NULL) {
 			if (type && *ok != 0) {
 				v->val = val_prepare(type);
@@ -3387,6 +3390,14 @@ function.
 		$0 = new_pos(binode, $1);
 		$0->op = Use;
 		$0->right = $<2;
+		if ($0->right->type == Xvar) {
+			struct var *v = cast(var, $0->right);
+			if (v->var->val.type == Tnone) {
+				/* Convert this to a label */
+				v->var->val = val_prepare(Tlabel);
+				v->var->val.label = &v->var->val;
+			}
+		}
 	}$
 
 ###### print binode cases
-- 
2.43.0