From 8ff1ac72c255c80796aa43ed645db90c545e6ac7 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Tue, 21 Apr 2026 17:11:46 +0300
Subject: [PATCH] ast: fix as cast cannot cast v.ast.unknowntypeinfo to
 v.ast.array (fixes #23704)

---
 vlib/v/ast/table.v      | 16 ++++++++++++----
 vlib/v/ast/table_test.v | 16 ++++++++++++++++
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/vlib/v/ast/table.v b/vlib/v/ast/table.v
index 9bb330246..cd28fbdae 100644
--- a/vlib/v/ast/table.v
+++ b/vlib/v/ast/table.v
@@ -1319,14 +1319,22 @@ pub fn (t &Table) known_type_idx(typ Type) bool {
 			return sym.language != .v || sym.name.starts_with('C.')
 		}
 		.array {
-			return t.known_type_idx((sym.info as Array).elem_type)
+			if sym.info is Array {
+				return t.known_type_idx(sym.info.elem_type)
+			}
+			return false
 		}
 		.array_fixed {
-			return t.known_type_idx((sym.info as ArrayFixed).elem_type)
+			if sym.info is ArrayFixed {
+				return t.known_type_idx(sym.info.elem_type)
+			}
+			return false
 		}
 		.map {
-			info := sym.info as Map
-			return t.known_type_idx(info.key_type) && t.known_type_idx(info.value_type)
+			if sym.info is Map {
+				return t.known_type_idx(sym.info.key_type) && t.known_type_idx(sym.info.value_type)
+			}
+			return false
 		}
 		else {}
 	}
diff --git a/vlib/v/ast/table_test.v b/vlib/v/ast/table_test.v
index 067b4edb4..e7deefef6 100644
--- a/vlib/v/ast/table_test.v
+++ b/vlib/v/ast/table_test.v
@@ -74,3 +74,19 @@ fn test_fully_unaliased_type_preserves_nested_c_alias_pointers() {
 	assert t.fully_unaliased_type(pwide_typ) == ast.u16_type.ref()
 	assert t.fully_unaliased_type(share_mode_typ) == ast.u32_type
 }
+
+fn test_known_type_names_skips_partial_array_symbols() {
+	mut t := ast.new_table()
+	broken_array_idx := t.register_sym(ast.TypeSymbol{
+		kind:     .array
+		name:     '[]Broken'
+		cname:    'Array_Broken'
+		mod:      'main'
+		is_pub:   true
+		language: .v
+	})
+	broken_array_type := ast.idx_to_type(broken_array_idx)
+
+	assert !t.known_type_idx(broken_array_type)
+	assert '[]Broken' !in t.known_type_names()
+}
-- 
2.39.5