U921-010: Avoid duplicates in completion

by using full sloc image comparison. This is needed in particular
for inherited subprograms coming from generic packages that are
instantiated multiple times: from the LAL perspective these nodes
are different, which is not what we want for completion.

An automatic test has been added.

Author: AnthonyLeonardoGracio

source/ada/lsp-ada_completions.adb

@@ -16,6 +16,7 @@
 ------------------------------------------------------------------------------
 
 with Ada.Containers.Hashed_Sets;
+with Langkit_Support;
 
 with VSS.Strings;
 
@@ -25,15 +26,16 @@ with LSP.Lal_Utils;
 
 package body LSP.Ada_Completions is
 
-   --------------
-   -- Is_Equal --
-   --------------
+   ------------------------
+   -- Is_Full_Sloc_Equal --
+   ------------------------
 
-   function Is_Equal (Left, Right : Libadalang.Analysis.Defining_Name)
-     return Boolean is
+   function Is_Full_Sloc_Equal
+     (Left, Right : Libadalang.Analysis.Defining_Name) return Boolean is
    begin
-      return Libadalang.Analysis."=" (Left, Right);
-   end Is_Equal;
+      return Libadalang.Analysis.Full_Sloc_Image
+          (Left) = Libadalang.Analysis.Full_Sloc_Image (Right);
+   end Is_Full_Sloc_Equal;
 
    -----------------------
    -- Write_Completions --

source/ada/lsp-ada_completions.ads

@@ -18,8 +18,10 @@
 --  This package provides types to support completions in Ada Language server.
 
 with Ada.Containers.Hashed_Maps;
+with Ada.Strings.Hash_Case_Insensitive;
 
 with Langkit_Support.Slocs;
+with Langkit_Support.Text;
 with Libadalang.Analysis;
 with Libadalang.Common;
 
@@ -32,12 +34,14 @@ package LSP.Ada_Completions is
 
    function Hash (Name : Libadalang.Analysis.Defining_Name)
      return Ada.Containers.Hash_Type is
-       (Name.As_Ada_Node.Hash);
+     (Ada.Strings.Hash_Case_Insensitive (
+        Langkit_Support.Text.To_UTF8 (Name.Full_Sloc_Image)));
 
-   function Is_Equal (Left, Right : Libadalang.Analysis.Defining_Name)
-     return Boolean;
-   --  This custom Is_Equal function is here as a temporary workaround.
-   --  The ticket for the corresponding compiler bug is T806-020.
+   function Is_Full_Sloc_Equal
+     (Left, Right : Libadalang.Analysis.Defining_Name) return Boolean;
+   --  Compare the two nodes using full sloc image (filename + sloc). Needed
+   --  for completion, since LAL can return several times the same declaration
+   --  and specially subprograms from generic instantiations.
 
    type Name_Information is record
       Is_Dot_Call  : Boolean;
@@ -59,7 +63,7 @@ package LSP.Ada_Completions is
      (Key_Type        => Libadalang.Analysis.Defining_Name,
       Element_Type    => Name_Information,
       Hash            => Hash,
-      Equivalent_Keys => Is_Equal,
+      Equivalent_Keys => Is_Full_Sloc_Equal,
       "="             => "=");
 
    type Completion_Provider is abstract tagged limited null record;

testsuite/ada_lsp/U921-010.completion.no_generic_duplicates/.cvsignore

@@ -0,0 +1 @@
+main

testsuite/ada_lsp/U921-010.completion.no_generic_duplicates/default.gpr

@@ -0,0 +1,6 @@
+project Default is
+
+   for Main use ("main.adb") & project'Main;
+
+end Default;
+

testsuite/ada_lsp/U921-010.completion.no_generic_duplicates/generic_pack.ads

@@ -0,0 +1,9 @@
+with Parents; use Parents;
+
+generic
+   A : Integer;
+package Generic_Pack is
+
+   type Child is new Parent with null record;
+
+end Generic_Pack;

testsuite/ada_lsp/U921-010.completion.no_generic_duplicates/main.adb

@@ -0,0 +1,10 @@
+with Generic_Pack;
+with Parents; use Parents;
+
+procedure Main is
+   package A is new Generic_Pack (3);
+   use A;
+
+begin
+   Prim  
+end Main;

testsuite/ada_lsp/U921-010.completion.no_generic_duplicates/parents.ads

@@ -0,0 +1,7 @@
+package Parents is
+
+   type Parent is tagged null record;
+
+   procedure Primitive (Obj : Parent) is null;
+   
+end Parents;