diff --git a/cmd/tools/vls.v b/cmd/tools/vls.v
index 9315d05793..2694621d89 100644
--- a/cmd/tools/vls.v
+++ b/cmd/tools/vls.v
@@ -154,8 +154,7 @@ fn (upd VlsUpdater) download_prebuilt() ! {
 	}
 
 	latest_release := releases_json[0].as_map()
-	latest_assets := latest_release['assets'] or { return }
-	assets := latest_assets.arr()
+	assets := latest_release['assets']!.arr()
 
 	mut checksum_asset_idx := -1
 	mut exec_asset_idx := -1
@@ -199,13 +198,11 @@ fn (upd VlsUpdater) download_prebuilt() ! {
 
 	upd.log('Executable found for this system. Downloading...')
 	upd.init_download_prebuilt()!
-	t_asset := exec_asset['browser_download_url'] or { return }
-	http.download_file(t_asset.str(), exec_asset_file_path)!
+	http.download_file(exec_asset['browser_download_url']!.str(), exec_asset_file_path)!
 
 	checksum_file_path := os.join_path(vls_cache_folder, 'checksums.txt')
 	checksum_file_asset := assets[checksum_asset_idx].as_map()
-	t_checksum_asset := checksum_file_asset['browser_download_url'] or { return }
-	http.download_file(t_checksum_asset.str(), checksum_file_path)!
+	http.download_file(checksum_file_asset['browser_download_url']!.str(), checksum_file_path)!
 	checksums := os.read_file(checksum_file_path)!.split_into_lines()
 
 	upd.log('Verifying checksum...')
diff --git a/doc/docs.md b/doc/docs.md
index 6cec3714d0..c7121bae41 100644
--- a/doc/docs.md
+++ b/doc/docs.md
@@ -1290,7 +1290,7 @@ large_index := 999
 val := arr[large_index] or { panic('out of bounds') }
 println(val)
 // you can also do this, if you want to *propagate* the access error:
-val2 := arr[333]?
+val2 := arr[333]!
 println(val2)
 ```
 
diff --git a/vlib/builtin/string_test.v b/vlib/builtin/string_test.v
index 68e3d64b59..f869780cce 100644
--- a/vlib/builtin/string_test.v
+++ b/vlib/builtin/string_test.v
@@ -144,16 +144,16 @@ fn test_ranges() {
 	assert s6 == 'first'
 }
 
-fn ranges_propagate_first(s string) ?string {
-	return s[10..]?
+fn ranges_propagate_first(s string) !string {
+	return s[10..]!
 }
 
-fn ranges_propagate_last(s string) ?string {
-	return s[..20]?
+fn ranges_propagate_last(s string) !string {
+	return s[..20]!
 }
 
-fn ranges_propagate_both(s string) ?string {
-	return s[1..20]?
+fn ranges_propagate_both(s string) !string {
+	return s[1..20]!
 }
 
 fn test_split_nth() {
diff --git a/vlib/toml/tests/crlf_test.v b/vlib/toml/tests/crlf_test.v
index 24c46ece02..f10eea4574 100644
--- a/vlib/toml/tests/crlf_test.v
+++ b/vlib/toml/tests/crlf_test.v
@@ -18,6 +18,6 @@ fn test_crlf_is_parsable_just_like_lf() {
 	for content in all {
 		res := toml.parse_text(content)?
 		assert res.value('title') == toml.Any('TOML Example')
-		assert (res.value('database') as map[string]toml.Any)['server']? == toml.Any('192.168.1.1')
+		assert (res.value('database') as map[string]toml.Any)['server']! == toml.Any('192.168.1.1')
 	}
 }
diff --git a/vlib/v/ast/type_size_test.v b/vlib/v/ast/type_size_test.v
index 4171cf1863..1821627068 100644
--- a/vlib/v/ast/type_size_test.v
+++ b/vlib/v/ast/type_size_test.v
@@ -41,21 +41,21 @@ fn test_type_size() {
 
 	mut t := b.table
 
-	size01, _ := t.type_size(t.type_idxs['main.T01']?)
+	size01, _ := t.type_size(t.type_idxs['main.T01']!)
 	assert sizeof(T01) == size01
-	size02, _ := t.type_size(t.type_idxs['main.T02']?)
+	size02, _ := t.type_size(t.type_idxs['main.T02']!)
 	assert sizeof(T02) == size02
-	size03, _ := t.type_size(t.type_idxs['main.T03']?)
+	size03, _ := t.type_size(t.type_idxs['main.T03']!)
 	assert sizeof(T03) == size03
-	size04, _ := t.type_size(t.type_idxs['main.T04']?)
+	size04, _ := t.type_size(t.type_idxs['main.T04']!)
 	assert sizeof(T04) == size04
-	size05, _ := t.type_size(t.type_idxs['main.T05']?)
+	size05, _ := t.type_size(t.type_idxs['main.T05']!)
 	assert sizeof(T05) == size05
-	size06, _ := t.type_size(t.type_idxs['main.T06']?)
+	size06, _ := t.type_size(t.type_idxs['main.T06']!)
 	assert sizeof(T06) == size06
-	size07, _ := t.type_size(t.type_idxs['main.T07']?)
+	size07, _ := t.type_size(t.type_idxs['main.T07']!)
 	assert sizeof(T07) == size07
-	size08, _ := t.type_size(t.type_idxs['main.T08']?)
+	size08, _ := t.type_size(t.type_idxs['main.T08']!)
 	assert sizeof(T08) == size08
 
 	println('done')
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 59303e9e3d..885050380e 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -952,7 +952,7 @@ pub fn (mut c Checker) check_expr_opt_call(expr ast.Expr, ret_type ast.Type) ast
 		}
 	} else if expr is ast.IndexExpr {
 		if expr.or_expr.kind != .absent {
-			c.check_or_expr(expr.or_expr, ret_type, ret_type.set_flag(.optional))
+			c.check_or_expr(expr.or_expr, ret_type, ret_type.set_flag(.result))
 		}
 	}
 	return ret_type
diff --git a/vlib/v/fmt/tests/empty_lines_keep.vv b/vlib/v/fmt/tests/empty_lines_keep.vv
index 876716e083..a99b63bfba 100644
--- a/vlib/v/fmt/tests/empty_lines_keep.vv
+++ b/vlib/v/fmt/tests/empty_lines_keep.vv
@@ -92,7 +92,7 @@ bar'
 }, Two{
     value: 'two'
 })"
-	r := m[key]?
+	r := m[key]!
 	compile_time_env := $env('ENV_VAR')
 	func()
 }
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index ad715ce362..bdd4f41135 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -2674,11 +2674,14 @@ fn (mut p Parser) index_expr(left ast.Expr, is_gated bool) ast.IndexExpr {
 					is_gated: is_gated
 				}
 			}
-			// `a[start..end] ?`
-			if p.tok.kind == .question {
+			// `a[start..end]!`
+			if p.tok.kind == .not {
 				or_pos_high = p.tok.pos()
-				or_kind_high = .propagate_option
+				or_kind_high = .propagate_result
 				p.next()
+			} else if p.tok.kind == .question {
+				p.error_with_pos('`?` for propagating errors from index expressions is no longer supported, use `!` instead of `?`',
+					p.tok.pos())
 			}
 		}
 
@@ -2740,11 +2743,14 @@ fn (mut p Parser) index_expr(left ast.Expr, is_gated bool) ast.IndexExpr {
 					is_gated: is_gated
 				}
 			}
-			// `a[start..end] ?`
-			if p.tok.kind == .question {
+			// `a[start..end]!`
+			if p.tok.kind == .not {
 				or_pos_low = p.tok.pos()
-				or_kind_low = .propagate_option
+				or_kind_low = .propagate_result
 				p.next()
+			} else if p.tok.kind == .question {
+				p.error_with_pos('`?` for propagating errors from index expressions is no longer supported, use `!` instead of `?`',
+					p.tok.pos())
 			}
 		}
 
@@ -2789,11 +2795,14 @@ fn (mut p Parser) index_expr(left ast.Expr, is_gated bool) ast.IndexExpr {
 				is_gated: is_gated
 			}
 		}
-		// `a[i] ?`
-		if p.tok.kind == .question {
+		// `a[i]!`
+		if p.tok.kind == .not {
 			or_pos = p.tok.pos()
-			or_kind = .propagate_option
+			or_kind = .propagate_result
 			p.next()
+		} else if p.tok.kind == .question {
+			p.error_with_pos('`?` for propagating errors from index expressions is no longer supported, use `!` instead of `?`',
+				p.tok.pos())
 		}
 	}
 	return ast.IndexExpr{
diff --git a/vlib/v/parser/tests/index_expr_optional_err.out b/vlib/v/parser/tests/index_expr_optional_err.out
new file mode 100644
index 0000000000..e91773916b
--- /dev/null
+++ b/vlib/v/parser/tests/index_expr_optional_err.out
@@ -0,0 +1,6 @@
+vlib/v/parser/tests/index_expr_optional_err.vv:3:14: error: `?` for propagating errors from index expressions is no longer supported, use `!` instead of `?`
+    1 | fn main() {
+    2 |     a := [1, 2]
+    3 |     println(a[0]?)
+      |                 ^
+    4 | }
diff --git a/vlib/v/parser/tests/index_expr_optional_err.vv b/vlib/v/parser/tests/index_expr_optional_err.vv
new file mode 100644
index 0000000000..f29bedbedb
--- /dev/null
+++ b/vlib/v/parser/tests/index_expr_optional_err.vv
@@ -0,0 +1,4 @@
+fn main() {
+	a := [1, 2]
+	println(a[0]?)
+}
diff --git a/vlib/v/tests/array_map_or_test.v b/vlib/v/tests/array_map_or_test.v
index 6e7142cc56..ee2d27b34f 100644
--- a/vlib/v/tests/array_map_or_test.v
+++ b/vlib/v/tests/array_map_or_test.v
@@ -51,26 +51,26 @@ fn test_map_or() {
 	assert good == 5
 }
 
-fn get_map_el(key string) ?int {
+fn get_map_el(key string) !int {
 	m := {
 		'as': 3
 		'qw': 4
 		'kl': 5
 	}
-	r := m[key]?
+	r := m[key]!
 	return r
 }
 
-fn get_arr_el(i int) ?int {
+fn get_arr_el(i int) !int {
 	m := [3, 4, 5]
-	r := m[i]?
+	r := m[i]!
 	return r
 }
 
 [direct_array_access]
-fn get_arr_el_direct(i int) ?int {
+fn get_arr_el_direct(i int) !int {
 	m := [3, 4, 5]
-	r := m[i]?
+	r := m[i]!
 	return r
 }
 
@@ -105,10 +105,10 @@ fn test_propagation() {
 	assert n == 3
 }
 
-fn get_arr_el_nested(i int) ?int {
+fn get_arr_el_nested(i int) !int {
 	ind := [2, 1, 0, 5]
 	m := [3, 4, 5]
-	r := m[ind[i]]?
+	r := m[ind[i]]!
 	return r
 }
 
diff --git a/vlib/v/tests/map_init_with_multi_enum_keys_test.v b/vlib/v/tests/map_init_with_multi_enum_keys_test.v
index 60f27a5ac8..9673287026 100644
--- a/vlib/v/tests/map_init_with_multi_enum_keys_test.v
+++ b/vlib/v/tests/map_init_with_multi_enum_keys_test.v
@@ -32,11 +32,11 @@ fn test_nested_map_init_with_multi_enum_keys() {
 		}
 	}
 	println(mp)
-	assert mp[.a]? == NestedAbc({
+	assert mp[.a]! == NestedAbc({
 		'A': 'AA'
 	})
-	assert mp[.b]? == NestedAbc('B')
-	assert mp[.c]? == NestedAbc({
+	assert mp[.b]! == NestedAbc('B')
+	assert mp[.c]! == NestedAbc({
 		'c': 'C'
 	})
 }
diff --git a/vlib/v/tests/nested_map_index_test.v b/vlib/v/tests/nested_map_index_test.v
index fee6fc6383..34ffbd935c 100644
--- a/vlib/v/tests/nested_map_index_test.v
+++ b/vlib/v/tests/nested_map_index_test.v
@@ -18,7 +18,7 @@ fn test_nested_map_index() {
 			}
 		}
 	}
-	ret := f.foo[11]?.bar[22]?
+	ret := f.foo[11]!.bar[22]!
 	println(ret)
 	assert ret == 'hello'
 }
diff --git a/vlib/v/tests/string_index_or_test.v b/vlib/v/tests/string_index_or_test.v
index f7c8611599..b0b0eeffa6 100644
--- a/vlib/v/tests/string_index_or_test.v
+++ b/vlib/v/tests/string_index_or_test.v
@@ -38,8 +38,8 @@ fn test_if_guard_good() {
 	assert res == '1'
 }
 
-fn get_propagate(s string, i int) ?string {
-	c := s[i]?
+fn get_propagate(s string, i int) !string {
+	c := s[i]!
 	return 'got `${c:c}`'
 }