From be18b7dc25da54ada1d102993a17ac27afbca5e4 Mon Sep 17 00:00:00 2001
From: Qyriad <qyriad@qyriad.me>
Date: Fri, 21 Nov 2025 12:53:51 +0100
Subject: [PATCH] parser: improve error message for missing semicolon in
 `inherit`

Before:
  error: syntax error, expecting ';'

After:
  error: syntax error, expecting ';' to end 'inherit' bindings


Change-Id: I47c633cb5c696b646840c58e03270a7d6a6a6964
---
 lix/libexpr/parser/grammar.hh                          | 10 +++++++++-
 lix/libexpr/parser/parser-impl1.inc.cc                 |  1 +
 tests/functional2/lang/inherit/in-unterminated.nix     |  8 ++++++++
 .../lang/inherit/parse-fail-unterminated.err.exp       |  6 ++++++
 4 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 tests/functional2/lang/inherit/in-unterminated.nix
 create mode 100644 tests/functional2/lang/inherit/parse-fail-unterminated.err.exp

diff --git a/lix/libexpr/parser/grammar.hh b/lix/libexpr/parser/grammar.hh
index 21607c15b..610df3ed2 100644
--- a/lix/libexpr/parser/grammar.hh
+++ b/lix/libexpr/parser/grammar.hh
@@ -203,6 +203,14 @@ struct sep : sor<
 
 using seps = star<t::sep>;
 
+// Delimiters.
+namespace d {
+    // Terminators.
+    namespace t {
+        struct inherit : one<';'> { };
+    }
+}
+
 
 // marker for semantic rules. not handling one of these in an action that cares about
 // semantics is probably an error.
@@ -411,7 +419,7 @@ struct inherit : _inherit, seq<
     t::kw_inherit, seps,
     opt<one<'('>, seps, _inherit::from, seps, must<one<')'>>, seps>,
     opt<_inherit::attrs, seps>,
-    must<one<';'>>
+    must<d::t::inherit>
 > {};
 
 struct _binding {
diff --git a/lix/libexpr/parser/parser-impl1.inc.cc b/lix/libexpr/parser/parser-impl1.inc.cc
index b81c23477..e9b8ded77 100644
--- a/lix/libexpr/parser/parser-impl1.inc.cc
+++ b/lix/libexpr/parser/parser-impl1.inc.cc
@@ -56,6 +56,7 @@ error_message_for(grammar::v1::expr::select) = "expecting selection expression";
 error_message_for(grammar::v1::t::kw_then) = "expecting 'then'";
 error_message_for(grammar::v1::t::kw_else) = "expecting 'else'";
 error_message_for(grammar::v1::t::kw_in) = "expecting 'in'";
+error_message_for(grammar::v1::d::t::inherit) = "expecting ';' to end 'inherit' bindings";
 
 struct SyntaxErrors
 {
diff --git a/tests/functional2/lang/inherit/in-unterminated.nix b/tests/functional2/lang/inherit/in-unterminated.nix
new file mode 100644
index 000000000..552812778
--- /dev/null
+++ b/tests/functional2/lang/inherit/in-unterminated.nix
@@ -0,0 +1,8 @@
+let
+  c = { };
+  b = 2;
+in {
+  a = b;
+  inherit c b
+  d = 5;
+}
diff --git a/tests/functional2/lang/inherit/parse-fail-unterminated.err.exp b/tests/functional2/lang/inherit/parse-fail-unterminated.err.exp
new file mode 100644
index 000000000..c378e4bcd
--- /dev/null
+++ b/tests/functional2/lang/inherit/parse-fail-unterminated.err.exp
@@ -0,0 +1,6 @@
+error: syntax error, expecting ';' to end 'inherit' bindings
+       at /pwd/in.nix:7:5:
+            6|   inherit c b
+            7|   d = 5;
+             |     ^
+            8| }