Add --warn-hide when a declaration hides a previous one.

For #652

2 files changed, 12 insertions, 6 deletions

diff --git a/src/vhdl/errorout.ads b/src/vhdl/errorout.ads
index 224f18cb9..ff7c54ada 100644
--- a/src/vhdl/errorout.ads
+++ b/src/vhdl/errorout.ads
@@ -103,6 +103,9 @@ package Errorout is
       --  Declaration of a shared variable with a non-protected type.
       Warnid_Shared,
 
+      --  A declaration hides a previous one.
+      Warnid_Hide,
+
       --  Emit a warning when a declaration is never used.
       --  FIXME: currently only subprograms are handled.
       Warnid_Unused,
diff --git a/src/vhdl/sem_scopes.adb b/src/vhdl/sem_scopes.adb
index e0589dc3f..17e3847ed 100644
--- a/src/vhdl/sem_scopes.adb
+++ b/src/vhdl/sem_scopes.adb
@@ -913,12 +913,15 @@ package body Sem_Scopes is
          end if;
       end if;
 
-      -- Homograph, not in the same scope.
-      -- LRM §10.3:
-      -- A declaration is said to be hidden within (part of) an inner
-      -- declarative region if the inner region contains an homograph
-      -- of this declaration; the outer declaration is the hidden
-      -- within the immediate scope of the inner homograph.
+      --  Homograph, not in the same scope.
+      --  LRM §10.3:
+      --  A declaration is said to be hidden within (part of) an inner
+      --  declarative region if the inner region contains an homograph
+      --  of this declaration; the outer declaration is the hidden
+      --  within the immediate scope of the inner homograph.
+      Warning_Msg_Sem (Warnid_Hide, +Decl,
+                       "declaration of %i hides %n", (+Decl, +Current_Decl));
+
       Add_New_Interpretation (True);
    end Add_Name;