5 files changed, 51 insertions, 1 deletions
diff --git a/gcc/rust/lex/rust-lex.cc b/gcc/rust/lex/rust-lex.cc
index ea09ac2..023b676 100644
--- a/gcc/rust/lex/rust-lex.cc
+++ b/gcc/rust/lex/rust-lex.cc
@@ -1856,6 +1856,35 @@ Lexer::parse_raw_identifier (Location loc)
     }
 }
 
+// skip broken string input (unterminated strings)
+void
+Lexer::skip_broken_string_input (int current_char)
+{
+  while (current_char != '"' && current_char != EOF)
+    {
+      if (current_char == '\n')
+	{
+	  current_line++;
+	  current_column = 1;
+	}
+      else
+	{
+	  current_column++;
+	}
+      skip_input ();
+      current_char = peek_input ();
+    }
+  if (current_char == '"')
+    {
+      current_column++;
+
+      skip_input ();
+      current_char = peek_input ();
+    }
+  rust_debug ("skipped to %d:%d due to bad quotes", current_line,
+	      current_column);
+}
+
 // Parses a unicode string.
 TokenPtr
 Lexer::parse_string (Location loc)
@@ -1903,6 +1932,9 @@ Lexer::parse_string (Location loc)
   if (current_char32.value == '\n')
     {
       rust_error_at (get_current_location (), "unended string literal");
+      // by this point, the parser will stuck at this position due to
+      // undetermined string termination. we now need to unstuck the parser
+      skip_broken_string_input (current_char32.value);
     }
   else if (current_char32.value == '"')
     {
diff --git a/gcc/rust/lex/rust-lex.h b/gcc/rust/lex/rust-lex.h
index e01d86d..429b9e1 100644
--- a/gcc/rust/lex/rust-lex.h
+++ b/gcc/rust/lex/rust-lex.h
@@ -114,6 +114,7 @@ private:
   Codepoint peek_codepoint_input ();
   Codepoint test_peek_codepoint_input (int n);
   void skip_codepoint_input ();
+  void skip_broken_string_input (int current_char);
 
   TokenPtr parse_byte_char (Location loc);
   TokenPtr parse_byte_string (Location loc);
diff --git a/gcc/rust/parse/rust-parse-impl.h b/gcc/rust/parse/rust-parse-impl.h
index dfd393e..0fc1c1f 100644
--- a/gcc/rust/parse/rust-parse-impl.h
+++ b/gcc/rust/parse/rust-parse-impl.h
@@ -914,7 +914,8 @@ Parser<ManagedTokenSource>::parse_delim_token_tree ()
 
   // repeat loop until finding the matching delimiter
   t = lexer.peek_token ();
-  while (!token_id_matches_delims (t->get_id (), delim_type))
+  while (!token_id_matches_delims (t->get_id (), delim_type)
+	 && t->get_id () != END_OF_FILE)
     {
       std::unique_ptr<AST::TokenTree> tok_tree = parse_token_tree ();
 
diff --git a/gcc/testsuite/rust/compile/torture/check-doc-attr-string.rs b/gcc/testsuite/rust/compile/torture/check-doc-attr-string.rs
new file mode 100644
index 0000000..33001c0
--- /dev/null
+++ b/gcc/testsuite/rust/compile/torture/check-doc-attr-string.rs
@@ -0,0 +1,13 @@
+#![crate_type = "lib"]
+
+#[doc(alias = "foo")] // ok!
+#[doc(alias("bar", "baz"))] // ok!
+pub struct Bar;
+
+#[doc(alias = "
+")] // { dg-error "unended string literal" "" { target *-*-* } .-1 }
+pub struct Foo;
+
+#[doc(alias("
+"))] // { dg-error "unended string literal" "" { target *-*-* } .-1 }
+pub struct Foo2;
diff --git a/gcc/testsuite/rust/compile/torture/very-broken-attr-string.rs b/gcc/testsuite/rust/compile/torture/very-broken-attr-string.rs
new file mode 100644
index 0000000..832ba7b
--- /dev/null
+++ b/gcc/testsuite/rust/compile/torture/very-broken-attr-string.rs
@@ -0,0 +1,3 @@
+// { dg-excess-errors "...." }
+// { dg-error "unended string literal" "" { target *-*-* } .+1 }
+#[doc(alias = "123