From 5918d5120f249654962a7fc5d8f823cbd93b495d Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Mon, 30 Sep 2024 21:32:33 +0200
Subject: [PATCH] Foreach over distinct pointer failed to be caught as error
 #1506.

---
 releasenotes.md                                 |  1 +
 src/compiler/sema_stmts.c                       | 17 +++++++++++++----
 .../statements/foreach_distinct_pointer_1506.c3 | 14 ++++++++++++++
 3 files changed, 28 insertions(+), 4 deletions(-)
 create mode 100644 test/test_suite/statements/foreach_distinct_pointer_1506.c3

diff --git a/releasenotes.md b/releasenotes.md
index 65dda63e1..fd48147fe 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -68,6 +68,7 @@
 - Fix bug when reading zip manifest, that would not return a zero terminated string. #1490
 - Fix thread tests.
 - Detect recursion errors on non-recursive mutexes in safe mode.
+- Foreach over distinct pointer failed to be caught as error #1506.
 
 ### Stdlib changes
 - Additional init functions for hashmap.
diff --git a/src/compiler/sema_stmts.c b/src/compiler/sema_stmts.c
index e2f794757..9cc877650 100644
--- a/src/compiler/sema_stmts.c
+++ b/src/compiler/sema_stmts.c
@@ -1442,15 +1442,15 @@ static inline bool sema_analyse_foreach_stmt(SemaContext *context, Ast *statemen
 	}
 
 	// Insert a single deref as needed.
-	Type *flattened_type = enumerator->type->canonical;
-	if (flattened_type->type_kind == TYPE_UNTYPED_LIST)
+	Type *canonical = enumerator->type->canonical;
+	if (canonical->type_kind == TYPE_UNTYPED_LIST)
 	{
 		RETURN_SEMA_ERROR(enumerator, "It is not possible to enumerate a compile time 'untyped' list at runtime, but you can use the compile time `$foreach` with the list.");
 	}
-	if (flattened_type->type_kind == TYPE_POINTER)
+	if (canonical->type_kind == TYPE_POINTER)
 	{
 		// Something like Foo** will not be dereferenced, only Foo*
-		if (flattened_type->pointer->type_kind == TYPE_POINTER)
+		if (canonical->pointer->type_kind == TYPE_POINTER)
 		{
 			RETURN_SEMA_ERROR(enumerator, "It is not possible to enumerate an expression of type %s.", type_quoted_error_string(enumerator->type));
 		}
@@ -1463,6 +1463,15 @@ static inline bool sema_analyse_foreach_stmt(SemaContext *context, Ast *statemen
 	// Check that we can even index this expression.
 
 	Type *value_type = type_get_indexed_type(enumerator->type);
+	// Special case, we might have "distinct Foo = char*" in which case the
+	// deref didn't happen above, but it will get a value_type.
+	// However, that would make the code later assume it's possible
+	// To use foreach on it.
+	if (canonical->type_kind == TYPE_DISTINCT && type_flatten(canonical)->type_kind == TYPE_POINTER)
+	{
+		value_type = NULL;
+	}
+
 	if (value_type && value_by_ref) value_type = type_get_ptr(value_type);
 
 	Decl *len = NULL;
diff --git a/test/test_suite/statements/foreach_distinct_pointer_1506.c3 b/test/test_suite/statements/foreach_distinct_pointer_1506.c3
new file mode 100644
index 000000000..5e6c2d262
--- /dev/null
+++ b/test/test_suite/statements/foreach_distinct_pointer_1506.c3
@@ -0,0 +1,14 @@
+distinct Type = char*;
+fn usz Type.len(str)
+{
+	return 0;
+}
+fn int main(String[] args)
+{
+  Type x = "AAAAA";  // Or ZString
+  foreach(y : x) // #error: It's not possible to enumerate an expression
+  {
+
+  }
+  return 0;
+}
\ No newline at end of file