# HG changeset patch
# User Bram Moolenaar <Bram@vim.org>
# Date 1595167204 -7200
# Node ID 8d58cbb07a1243b613aa2c85f7b2679f54fddcfc
# Parent  e29093c09d58a227057a0eef9952f6895e962d01
patch 8.2.1244: Vim9: in lambda index assumes a list

Commit: https://github.com/vim/vim/commit/6802cce407b8b181bcf3eafe701fa9f8a91f7a73
Author: Bram Moolenaar <Bram@vim.org>
Date:   Sun Jul 19 15:49:49 2020 +0200

    patch 8.2.1244: Vim9: in lambda index assumes a list

    Problem:    Vim9: in lambda index assumes a list.
    Solution:   Use the value type to decide about list or dict. (closes https://github.com/vim/vim/issues/6479)

diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -1115,7 +1115,7 @@ def Test_expr7_list()
   call CheckDefExecFailure(["let x = g:anint[3]"], 'E714:')
   call CheckDefFailure(["let x = g:list_mixed[xxx]"], 'E1001:')
   call CheckDefFailure(["let x = [1,2,3]"], 'E1069:')
-  call CheckDefExecFailure(["let x = g:list_mixed['xx']"], 'E39:')
+  call CheckDefExecFailure(["let x = g:list_mixed['xx']"], 'E1029:')
   call CheckDefFailure(["let x = g:list_mixed["], 'E1097:')
   call CheckDefFailure(["let x = g:list_mixed[0"], 'E1097:')
   call CheckDefExecFailure(["let x = g:list_empty[3]"], 'E684:')
@@ -1173,6 +1173,9 @@ def Test_expr7_lambda()
 	})
   assert_equal([111, 222, 111], ll)
 
+  let dl = [{'key': 0}, {'key': 22}]->filter({ _, v -> v['key'] })
+  assert_equal([{'key': 22}], dl)
+
   call CheckDefFailure(["filter([1, 2], {k,v -> 1})"], 'E1069:')
 enddef
 
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1244,
+/**/
     1243,
 /**/
     1242,
diff --git a/src/vim9compile.c b/src/vim9compile.c
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -3748,6 +3748,7 @@ compile_subscript(
 	{
 	    garray_T	*stack = &cctx->ctx_type_stack;
 	    type_T	**typep;
+	    vartype_T	vtype;
 
 	    // list index: list[123]
 	    // dict member: dict[key]
@@ -3773,22 +3774,38 @@ compile_subscript(
 	    }
 	    *arg = *arg + 1;
 
+	    // We can index a list and a dict.  If we don't know the type
+	    // we can use the index value type.
+	    // TODO: If we don't know use an instruction to figure it out at
+	    // runtime.
 	    typep = ((type_T **)stack->ga_data) + stack->ga_len - 2;
-	    if ((*typep)->tt_type == VAR_LIST || (*typep) == &t_any)
+	    vtype = (*typep)->tt_type;
+	    if (*typep == &t_any)
+	    {
+		type_T *valtype = ((type_T **)stack->ga_data)
+							   [stack->ga_len - 1];
+		if (valtype == &t_string)
+		    vtype = VAR_DICT;
+	    }
+	    if (vtype == VAR_DICT)
+	    {
+		if ((*typep)->tt_type == VAR_DICT)
+		    *typep = (*typep)->tt_member;
+		else if (need_type(*typep, &t_dict_any, -2, cctx, FALSE)
+								       == FAIL)
+		    return FAIL;
+		if (may_generate_2STRING(-1, cctx) == FAIL)
+		    return FAIL;
+		if (generate_instr_drop(cctx, ISN_MEMBER, 1) == FAIL)
+		    return FAIL;
+	    }
+	    else if (vtype == VAR_LIST || *typep == &t_any)
 	    {
 		if ((*typep)->tt_type == VAR_LIST)
 		    *typep = (*typep)->tt_member;
 		if (generate_instr_drop(cctx, ISN_INDEX, 1) == FAIL)
 		    return FAIL;
 	    }
-	    else if ((*typep)->tt_type == VAR_DICT)
-	    {
-		*typep = (*typep)->tt_member;
-		if (may_generate_2STRING(-1, cctx) == FAIL)
-		    return FAIL;
-		if (generate_instr_drop(cctx, ISN_MEMBER, 1) == FAIL)
-		    return FAIL;
-	    }
 	    else
 	    {
 		emsg(_(e_listdictblobreq));
@@ -5386,7 +5403,7 @@ compile_assignment(char_u *arg, exarg_T 
 		}
 
 		stacktype = stack->ga_len == 0 ? &t_void
-			  : ((type_T **)stack->ga_data)[stack->ga_len - 1];
+			      : ((type_T **)stack->ga_data)[stack->ga_len - 1];
 		if (lvar != NULL && (is_decl || !has_type))
 		{
 		    if (new_local && !has_type)