Debug information about extra arguments from __call

'debug.getinfo' can return number of extra arguments added to a call by
a chain of __call metavalues. That information is being used to improve
error messages about errors in these extra arguments.

1 files changed, 11 insertions, 2 deletions

diff --git a/manual/manual.of b/manual/manual.of
index ce42ff51..a441cea1 100644
--- a/manual/manual.of
+++ b/manual/manual.of
@@ -4850,6 +4850,7 @@ typedef struct lua_Debug {
   unsigned char nups;         /* (u) number of upvalues */
   unsigned char nparams;      /* (u) number of parameters */
   char isvararg;              /* (u) */
+  unsigned char extraargs;    /* (t) number of extra arguments */
   char istailcall;            /* (t) */
   int ftransfer;              /* (r) index of first value transferred */
   int ntransfer;              /* (r) number of transferred values */
@@ -4938,6 +4939,14 @@ true if this function invocation was called by a tail call.
 In this case, the caller of this level is not in the stack.
 }
 
+@item{@id{extraargs}|
+The number of extra arguments added by the call
+to functions called through @idx{__call} metamethods.
+(Each @idx{__call} metavalue adds a single extra argument,
+the object being called,
+but there may be a chain of @idx{__call} metavalues.)
+}
+
 @item{@id{nups}|
 the number of upvalues of the function.
 }
@@ -5045,7 +5054,7 @@ fills in the fields @id{source}, @id{short_src},
 @id{linedefined}, @id{lastlinedefined}, and @id{what};
 }
 
-@item{@Char{t}| fills in the field @id{istailcall};
+@item{@Char{t}| fills in the fields @id{istailcall} and @id{extraargs};
 }
 
 @item{@Char{u}| fills in the fields
@@ -7993,7 +8002,7 @@ returns @fail plus the position of the first invalid byte.
 
 @LibEntry{utf8.offset (s, n [, i])|
 
-Returns the the position of the @id{n}-th character of @id{s}
+Returns the position of the @id{n}-th character of @id{s}
 (counting from byte position @id{i}) as two integers:
 The index (in bytes) where its encoding starts and the
 index (in bytes) where it ends.