Warn about exported variables

Fix the reported warning in `credit_flow.erl` and `rabbit_table.erl`.

This is the default setting in erlang.mk, so fixing this directly in
RabbitMQ will ease future work on erlang.mk or Rebar.

3 files changed, 10 insertions, 7 deletions

diff --git a/Makefile b/Makefile
index 1c9800188e..22f8270a07 100644
--- a/Makefile
+++ b/Makefile
@@ -61,7 +61,7 @@ USE_PROPER_QC:=$(shell erl -noshell -eval 'io:format({module, proper} =:= code:e
 endif
 
 #other args: +native +"{hipe,[o3,verbose]}" -Ddebug=true +debug_info +no_strict_record_tests
-ERLC_OPTS=-I $(INCLUDE_DIR) -Wall -v +debug_info $(call boolean_macro,$(USE_SPECS),use_specs) $(call boolean_macro,$(USE_PROPER_QC),use_proper_qc)
+ERLC_OPTS=-I $(INCLUDE_DIR) -Wall +warn_export_vars -v +debug_info $(call boolean_macro,$(USE_SPECS),use_specs) $(call boolean_macro,$(USE_PROPER_QC),use_proper_qc)
 
 ifdef INSTRUMENT_FOR_QC
 ERLC_OPTS += -DINSTR_MOD=gm_qc
diff --git a/src/credit_flow.erl b/src/credit_flow.erl
index 6b24175388..e7f13a66dc 100644
--- a/src/credit_flow.erl
+++ b/src/credit_flow.erl
@@ -61,9 +61,9 @@
             %% We deliberately allow Var to escape from the case here
             %% to be used in Expr. Any temporary var we introduced
             %% would also escape, and might conflict.
-            case get(Key) of
-                undefined -> Var = Default;
-                Var       -> ok
+            Var = case get(Key) of
+                undefined -> Default;
+                V         -> V
             end,
             put(Key, Expr)
         end).
diff --git a/src/rabbit_table.erl b/src/rabbit_table.erl
index e716345b85..a873a714e1 100644
--- a/src/rabbit_table.erl
+++ b/src/rabbit_table.erl
@@ -189,9 +189,12 @@ check_content(Tab, TabDef) ->
 
 check(Fun) ->
     case [Error || {Tab, TabDef} <- definitions(),
-                   case Fun(Tab, TabDef) of
-                       ok             -> Error = none, false;
-                       {error, Error} -> true
+                   begin
+                       {Ret, Error} = case Fun(Tab, TabDef) of
+                           ok         -> {false, none};
+                           {error, E} -> {true, E}
+                       end,
+                       Ret
                    end] of
         []     -> ok;
         Errors -> {error, Errors}