V901-009: Generate Signatures using the Parameter completion

Add test for signatureHelp and generic instantiation.
Add tests for signatureHelp and aggregates.

Author: AdrienBoulanger

source/ada/lsp-ada_completions-generic_assoc.adb

@@ -39,17 +39,31 @@ generic
    with function Get_Designators
      (E              : Element;
       Sloc           : Langkit_Support.Slocs.Source_Location;
+      Prefixed       : out Boolean;
       Unnamed_Params : out Natural)
       return Laltools.Common.Node_Vectors.Vector;
-   --  Return the current list of Designators for E.
-   --  Unnamed_Params correspond to the number of parameters without
-   --  designators before Sloc.
+   --  Compute the list of parameters in E, they are separated in 4 categories:
+   --  - Prefixed indicates if we are prefixed by a parameter
+   --  - Unnamed_Params corresponds to all the params without designators
+   --  at the start of the function
+   --  - The Result starts with the list of all the designators
+   --  - The Result finishes with X No_Ada_Node, one for each params without
+   --  designator after the first named param.
+   --
+   --  Example: Obj.Foo (1, 2, 3, X => 4, Y => 5, 7, 8
+   --  Prefixed       = Is_Param (Obj)
+   --  Unnamed_Params = 3
+   --  Result         = [X, Y, No_Ada_Node, No_Ada_Node]
 
    with function Get_Spec_Designators
-     (E       : Element;
-      Context : not null LSP.Ada_Handlers.Context_Access)
+     (E             : Element;
+      Context       : not null LSP.Ada_Handlers.Context_Access;
+      For_Signature : Boolean)
       return LSP.Ada_Completions.Generic_Assoc_Utils.Assoc_Data_Lists.List;
    --  Return all the specs matching E
+   --  When For_Signature, modify the data for signature
+   --  For example: completion requires the missing parameters but signature
+   --  requires all parameters
 
    Pretty_Print_Rule : Libadalang.Common.Grammar_Rule;
    --  Rule used to pretty print the completion item
@@ -60,6 +74,10 @@ generic
       return Libadalang.Analysis.Ada_Node'Class;
    --  Get the node needed to match Pretty_Print_Rule
    --  Column represent the block indentation level
+
+   with function To_Node
+     (E : Element) return Libadalang.Analysis.Ada_Node'Class;
+
 package LSP.Ada_Completions.Generic_Assoc is
    procedure Propose_Completion
      (Self         :
@@ -71,4 +89,14 @@ package LSP.Ada_Completions.Generic_Assoc is
       Filter       : in out LSP.Ada_Completions.Filters.Filter;
       Names        : in out Ada_Completions.Completion_Maps.Map;
       Unsorted_Res : in out LSP.Messages.CompletionItem_Vector);
+
+   procedure Propose_Signatures
+     (Context         : not null LSP.Ada_Handlers.Context_Access;
+      Node            : Libadalang.Analysis.Ada_Node;
+      Cursor          : Langkit_Support.Slocs.Source_Location;
+      Prev_Signatures : LSP.Messages.Optional_SignatureHelpContext;
+      Res             : in out LSP.Messages.SignatureHelp;
+      Lazy            : Boolean := False);
+   --  If Lazy, give up on trying to highlight the parameters when multiple
+   --  signature are possible.
 end LSP.Ada_Completions.Generic_Assoc;