insert-mode: interpret unmapped META as ESC

closes #2454
closes #8213
ref #7972

3 files changed, 46 insertions, 31 deletions

diff --git a/test/functional/insert/insert_spec.lua b/test/functional/insert/insert_spec.lua
new file mode 100644
index 0000000000..427954f5a6
--- /dev/null
+++ b/test/functional/insert/insert_spec.lua
@@ -0,0 +1,41 @@
+local helpers = require('test.functional.helpers')(after_each)
+local clear, feed, insert = helpers.clear, helpers.feed, helpers.insert
+local command = helpers.command
+local eq = helpers.eq
+local expect = helpers.expect
+local funcs = helpers.funcs
+
+describe('insert-mode', function()
+  before_each(function()
+    clear()
+  end)
+
+  it('CTRL-@', function()
+    -- Inserts last-inserted text, leaves insert-mode.
+    insert('hello')
+    feed('i<C-@>x')
+    expect('hellhello')
+
+    -- C-Space is the same as C-@.
+    -- CTRL-SPC inserts last-inserted text, leaves insert-mode.
+    feed('i<C-Space>x')
+    expect('hellhellhello')
+
+    -- CTRL-A inserts last inserted text
+    feed('i<C-A>x')
+    expect('hellhellhellhelloxo')
+  end)
+
+  it('ALT/META #8213', function()
+    -- Mapped ALT-chord behaves as mapped.
+    command('inoremap <M-l> meta-l')
+    command('inoremap <A-j> alt-j')
+    feed('i<M-l> xxx <A-j><M-h>a<A-h>')
+    expect('meta-l xxx alt-j')
+    eq({ 0, 1, 14, 0, }, funcs.getpos('.'))
+    -- Unmapped ALT-chord behaves as ESC+c.
+    command('iunmap <M-l>')
+    feed('0i<M-l>')
+    eq({ 0, 1, 2, 0, }, funcs.getpos('.'))
+  end)
+end)
diff --git a/test/functional/insert/last_inserted_spec.lua b/test/functional/insert/last_inserted_spec.lua
deleted file mode 100644
index dce23a3790..0000000000
--- a/test/functional/insert/last_inserted_spec.lua
+++ /dev/null
@@ -1,22 +0,0 @@
-local helpers = require('test.functional.helpers')(after_each)
-local clear, feed, insert = helpers.clear, helpers.feed, helpers.insert
-local expect = helpers.expect
-
-clear()
-
-describe('insert-mode', function()
-  it('CTRL-@ inserts last-inserted text, leaves insert-mode', function()
-    insert('hello')
-    feed('i<C-@>x')
-    expect('hellhello')
-  end)
-  -- C-Space is the same as C-@
-  it('CTRL-SPC inserts last-inserted text, leaves insert-mode', function()
-    feed('i<C-Space>x')
-    expect('hellhellhello')
-  end)
-  it('CTRL-A inserts last inserted text', function()
-    feed('i<C-A>x')
-    expect('hellhellhellhelloxo')
-  end)
-end)
diff --git a/test/functional/terminal/tui_spec.lua b/test/functional/terminal/tui_spec.lua
index 171745eb57..2f9abfd3f6 100644
--- a/test/functional/terminal/tui_spec.lua
+++ b/test/functional/terminal/tui_spec.lua
@@ -115,16 +115,12 @@ describe('tui', function()
     ]])
   end)
 
-  it('does not mangle unmapped ALT-key chord', function()
-    -- Vim represents ALT/META by setting the "high bit" of the modified key;
-    -- we do _not_. #3982
-    --
-    -- Example: for input ALT+j:
-    --    * Vim (Nvim prior to #3982) sets high-bit, inserts "ê".
-    --    * Nvim (after #3982) inserts "j".
-    feed_data('i\027j')
+  it('interprets ESC+key as ALT chord', function()
+    -- Vim represents ALT/META by setting the "high bit" of the modified key:
+    -- ALT+j inserts "ê". Nvim does not (#3982).
+    feed_data('i\022\027j')
     screen:expect([[
-      j{1: }                                                |
+      <M-j>{1: }                                            |
       {4:~                                                 }|
       {4:~                                                 }|
       {4:~                                                 }|