From b1633b9ebb68cb682a656f1026056f77afcdfb45 Mon Sep 17 00:00:00 2001
From: gingerBill <gingerBill@users.noreply.github.com>
Date: Wed, 11 Feb 2026 14:05:06 +0000
Subject: [PATCH] Require all values from a procedure iterator if the procedure
 is marked with `@(require_results)`

---
 src/check_stmt.cpp | 19 +++++++++++++++++--
 src/parser.cpp     | 16 ++++++++++++++++
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/src/check_stmt.cpp b/src/check_stmt.cpp
index 1f433df36..66283d3da 100644
--- a/src/check_stmt.cpp
+++ b/src/check_stmt.cpp
@@ -1724,6 +1724,7 @@ gb_internal void check_range_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags)
 	bool is_range = false;
 	bool is_possibly_addressable = true;
 	isize max_val_count = 2;
+
 	if (is_ast_range(expr)) {
 		ast_node(ie, BinaryExpr, expr);
 		Operand x = {};
@@ -1884,7 +1885,7 @@ gb_internal void check_range_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags)
 						error_line("\tMultiple return valued parameters in a range statement are limited to a minimum of 1 usable values with a trailing boolean for the conditional, got %td\n", count);
 						break;
 					}
-					enum : isize {MAXIMUM_COUNT = 100};
+					enum : isize {MAXIMUM_COUNT = 20};
 					if (count > MAXIMUM_COUNT) {
 						ERROR_BLOCK();
 						check_not_tuple(ctx, &operand);
@@ -1900,7 +1901,7 @@ gb_internal void check_range_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags)
 						break;
 					}
 
-					max_val_count = count;
+					max_val_count = count-1;
 
 					for (Entity *e : t->Tuple.variables) {
 						array_add(&vals, e->type);
@@ -1920,6 +1921,20 @@ gb_internal void check_range_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags)
 					if (is_reverse) {
 						error(node, "#reverse for is not supported for multiple return valued parameters");
 					}
+
+					Ast *expr = unparen_expr(operand.expr);
+					if (expr->kind == Ast_CallExpr) {
+						Type *p = base_type(type_of_expr(expr->CallExpr.proc));
+						if (p != nullptr && p->kind == Type_Proc) {
+							if (p->Proc.require_results) {
+								if (rs->vals.count < max_val_count) {
+									TokenPos start = ast_token(rs->vals[0]).pos;
+									TokenPos end   = ast_end_pos(rs->vals[rs->vals.count-1]);
+									error_range(start, end, "Expected a %td identifier%s, got %td", max_val_count, max_val_count == 1 ? "" : "s", rs->vals.count);
+								}
+							}
+						}
+					}
 				}
 				break;
 
diff --git a/src/parser.cpp b/src/parser.cpp
index 0efe2714a..159eb65f8 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -514,6 +514,22 @@ gb_internal void error(Ast *node, char const *fmt, ...) {
 	}
 }
 
+gb_internal void error_range(TokenPos start, TokenPos end, char const *fmt, ...) {
+	GB_ASSERT(start.file_id == end.file_id);
+	GB_ASSERT(start.line == end.line);
+	GB_ASSERT(start.column <= end.column);
+	GB_ASSERT(start.offset <= end.offset);
+
+	va_list va;
+	va_start(va, fmt);
+	error_va(start, end, fmt, va);
+	va_end(va);
+	if (start.file_id != 0) {
+		AstFile *f = thread_safe_get_ast_file_from_id(start.file_id);
+		f->error_count += 1;
+	}
+}
+
 gb_internal void syntax_error_with_verbose(Ast *node, char const *fmt, ...) {
 	Token token = {};
 	TokenPos end_pos = {};