Add -Wunused-module.

* module/language/tree-il/analyze.scm (<module-info>): New record type.
(unused-module-analysis): New variable.
(make-unused-module-analysis): New analysis.
(make-analyzer): Add it.
* module/system/base/message.scm (%warning-types): Add 'unused-module'.
* test-suite/tests/tree-il.test (%opts-w-unused-module): New variable.
("warnings")["unused-module"]: New test prefix.
* NEWS: Update.

1 files changed, 17 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index 4313880c7..a0009406f 100644
--- a/NEWS
+++ b/NEWS
@@ -5,6 +5,23 @@ See the end for copying conditions.
 Please send Guile bug reports to bug-guile@gnu.org.
 
 
+Changes in 3.0.10 (since 3.0.9)
+
+* New interfaces and functionality
+
+** New warning: unused-module
+
+This analysis, enabled at `-W2', issues warnings for modules that appear
+in a `use-modules' form or as a #:use-module clause of `define-module',
+and whose bindings are unused.  This is useful to trim the list of
+imports of a module.
+
+In some cases, the compiler cannot conclude whether a module is
+definitely unused---this is notably the case for modules that are only
+used at macro-expansion time, such as (srfi srfi-26).  In those cases,
+the compiler reports it as "possibly unused".
+
+
 Changes in 3.0.9 (since 3.0.8)
 
 * Notable changes