From 4bd10b6fe81c0a56eb9e01e24fba10e655966870 Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Tue, 29 Dec 2020 13:15:54 -0300
Subject: Better error messages for calling non-callable objects

When available, use the calling code to find a suitable name for what
was being called; this is particularly useful for errors of non-callable
metamethods. This commit also improved the debug information for
order metamethods.
---
 testes/db.lua     |  6 ++++--
 testes/errors.lua | 14 +++++++++++++-
 testes/locals.lua | 17 ++++++++++++++++-
 3 files changed, 33 insertions(+), 4 deletions(-)

(limited to 'testes')

diff --git a/testes/db.lua b/testes/db.lua
index fdb0da4a..ce559ad9 100644
--- a/testes/db.lua
+++ b/testes/db.lua
@@ -823,8 +823,10 @@ assert(a + 30000 == "add" and a - 3.0 == "sub" and a * 3.0 == "mul" and
        -a == "unm" and #a == "len" and a & 3 == "band")
 assert(a|3 == "bor" and 3~a == "bxor" and a<<3 == "shl" and a>>1 == "shr")
 assert (a==b and a.op == "eq")
-assert (a>=b and a.op == "order")
-assert (a>b and a.op == "order")
+assert (a>=b and a.op == "le")
+assert ("x">=a and a.op == "le")
+assert (a>b and a.op == "lt")
+assert (a>10 and a.op == "lt")
 assert(~a == "bnot")
 
 do   -- testing for-iterator name
diff --git a/testes/errors.lua b/testes/errors.lua
index a3f07021..4249f570 100644
--- a/testes/errors.lua
+++ b/testes/errors.lua
@@ -24,8 +24,9 @@ local function doit (s)
 end
 
 
-local function checkmessage (prog, msg)
+local function checkmessage (prog, msg, debug)
   local m = doit(prog)
+  if debug then print(m) end
   assert(string.find(m, msg, 1, true))
 end
 
@@ -120,6 +121,17 @@ assert(not string.find(doit"a={13}; local bbbb=1; a[bbbb](3)", "'bbbb'"))
 checkmessage("a={13}; local bbbb=1; a[bbbb](3)", "number")
 checkmessage("a=(1)..{}", "a table value")
 
+-- calls
+checkmessage("local a; a(13)", "local 'a'")
+checkmessage([[
+  local a = setmetatable({}, {__add = 34})
+  a = a + 1
+]], "metamethod 'add'")
+checkmessage([[
+  local a = setmetatable({}, {__lt = {}})
+  a = a > a
+]], "metamethod 'lt'")
+
 -- tail calls
 checkmessage("local a={}; return a.bbbb(3)", "field 'bbbb'")
 checkmessage("a={}; do local a=1 end; return a:bbbb(3)", "method 'bbbb'")
diff --git a/testes/locals.lua b/testes/locals.lua
index 1b43609b..add023ca 100644
--- a/testes/locals.lua
+++ b/testes/locals.lua
@@ -459,7 +459,22 @@ do   -- errors due to non-closable values
     getmetatable(xyz).__close = nil   -- remove metamethod
   end
   local stat, msg = pcall(foo)
-  assert(not stat and string.find(msg, "attempt to call a nil value"))
+  assert(not stat and string.find(msg, "metamethod 'close'"))
+
+  local function foo ()
+    local a1 <close> = func2close(function (_, msg)
+      assert(string.find(msg, "number value"))
+      error(12)
+    end)
+    local a2 <close> = setmetatable({}, {__close = print})
+    local a3 <close> = func2close(function (_, msg)
+      assert(msg == nil)
+      error(123)
+    end)
+    getmetatable(a2).__close = 4   -- invalidate metamethod
+  end
+  local stat, msg = pcall(foo)
+  assert(not stat and msg == 12)
 end
 
 
-- 
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