indent: for '.<expr>;' cases, uses searchpair heuristics

Fixes rust-lang#366.

Author: da-x

indent/rust.vim

@@ -191,7 +191,12 @@ function GetRustIndent(lnum)
     " A line that ends with '.<expr>;' is probably an end of a long list
     " of method operations.
     if prevline =~# '\V\^\s\*.' && l:last_prevline_character ==# ';'
-        return indent(prevlinenum) - s:shiftwidth()
+        call cursor(a:lnum - 1, 1)
+        let l:scope_start = searchpair('{\|(', '', '}\|)', 'nbW',
+                    \ 's:is_string_comment(line("."), col("."))')
+        if l:scope_start != 0 && l:scope_start < a:lnum
+            return indent(l:scope_start) + 4
+        endif
     endif
 
     if l:last_prevline_character ==# ","

test/indent.vader

@@ -225,6 +225,51 @@ Expect rust (issue #5):
       }
   }
 
+############################################
+# Issue #366
+
+Given rust:
+  fn f() {
+      g(|_| {
+          h();
+      })
+      .unwrap();
+      h();
+  }
+
+Do:
+  vip=
+
+Expect rust (issue #366):
+  fn f() {
+      g(|_| {
+          h();
+      })
+      .unwrap();
+      h();
+  }
+
+Given rust:
+  fn f() {
+      let a = g(|_| {
+              h();
+          })
+          .unwrap();
+      h();
+  }
+
+Do:
+  vip=
+
+Expect rust (issue #366, variation #2):
+  fn f() {
+      let a = g(|_| {
+          h();
+      })
+      .unwrap();
+      h();
+  }
+
 ############################################
 
 Given rust: