`for &e, i in array` and `for k, &v in map` (alternative to passing the iterable by pointer)

1 files changed, 9 insertions, 1 deletions

diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index 83e44b39f..532555b0a 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -2273,7 +2273,15 @@ gb_internal void check_unary_expr(CheckerContext *c, Operand *o, Token op, Ast *
 							defer (end_error_block());
 							error(op, "Cannot take the pointer address of '%s'", str);
 							if (e != nullptr && (e->flags & EntityFlag_ForValue) != 0) {
-								error_line("\tSuggestion: Did you want to pass the iterable value to the for statement by pointer to get addressable semantics?\n");
+								Type *parent_type = type_deref(e->Variable.for_loop_parent_type);
+
+								if (parent_type != nullptr && is_type_string(parent_type)) {
+									error_line("\tSuggestion: Iterating over a string produces an intermediate 'rune' value which cannot be addressed.\n");
+								} else if (parent_type != nullptr && is_type_tuple(parent_type)) {
+									error_line("\tSuggestion: Iterating over a procedure does not produce values which are addressable.\n");
+								} else {
+									error_line("\tSuggestion: Did you want to pass the iterable value to the for statement by pointer to get addressable semantics?\n");
+								}
 							}
 							if (e != nullptr && (e->flags & EntityFlag_SwitchValue) != 0) {
 								error_line("\tSuggestion: Did you want to pass the value to the switch statement by pointer to get addressable semantics?\n");