Fix indentation for c-ts-mode (bug#61026)

Fix indentation for things like

  while (true)
    if (true)
      {
        puts ("Hello");
      }

Note that the outer while loop omits brackets.

* lisp/progmodes/c-ts-mode.el:
(c-ts-mode--statement-offset-post-processr): New variable.
(c-ts-mode--statement-offset): Use the new function.
(c-ts-mode--fix-bracketless-indent): New function.
(c-ts-base-mode): Use the new function.
* test/lisp/progmodes/c-ts-mode-resources/indent.erts: New tests.

1 files changed, 52 insertions, 0 deletions

diff --git a/test/lisp/progmodes/c-ts-mode-resources/indent.erts b/test/lisp/progmodes/c-ts-mode-resources/indent.erts
index b8524432d02..67654404a77 100644
--- a/test/lisp/progmodes/c-ts-mode-resources/indent.erts
+++ b/test/lisp/progmodes/c-ts-mode-resources/indent.erts
@@ -105,6 +105,58 @@ main (int   argc,
 }
 =-=-=
 
+Name: Bracket-less Block-Statement (GNU Style) (bug#61026)
+
+=-=
+int main() {
+  while (true)
+    if (true)
+      {
+        puts ("Hello");
+      }
+  for (int i=0; i<5; i++)
+    if (true)
+      {
+        puts ("Hello");
+      }
+  do
+    if (true)
+      {
+        puts ("Hello");
+      }
+  while (true);
+  if (true)
+    if (true)
+      {
+        puts ("Hello");
+      }
+}
+=-=-=
+
+Name: Bracket-less Block-Statement (Linux Style) (bug#61026)
+
+=-=-=
+int main() {
+  while (true)
+    if (true) {
+      puts ("Hello");
+    }
+  for (int i=0; i<5; i++)
+    if (true) {
+      puts ("Hello");
+    }
+  do
+    if (true) {
+      puts ("Hello");
+    }
+  while (true);
+  if (true)
+    if (true) {
+      puts ("Hello");
+    }
+}
+=-=-=
+
 Name: Multiline Parameter List (bug#60398)
 
 =-=