commit 05a5551a86e013e35d1dfa10fd0d811c587f9c88
author Bram Moolenaar <Bram@vim.org> Sun Jul 05 15:52:19 2020 +0200
committer Bram Moolenaar <Bram@vim.org> Sun Jul 05 15:52:19 2020 +0200
tree fdff5341055cc148712c4603f39a02c2a3f951d2
parent 788123c00c4b7acc4e6ba3e9f1cc8b175ae9aae8

patch 8.2.1131: Vim9: error message for returning a value is not clear

Problem:    Vim9: error message for returning a value in a function that does
            not return anything is not clear.
Solution:   Add a specific message.

src/testdir/test_vim9_func.vim

diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 6a03edd..583a232 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -286,14 +286,14 @@
 
 def Test_error_in_nested_function()
   " Error in called function requires unwinding the call stack.
-  assert_fails('call FuncWithForwardCall()', 'E1013')
+  assert_fails('call FuncWithForwardCall()', 'E1096')
 enddef
 
 def Test_return_type_wrong()
   CheckScriptFailure(['def Func(): number', 'return "a"', 'enddef', 'defcompile'], 'expected number but got string')
   CheckScriptFailure(['def Func(): string', 'return 1', 'enddef', 'defcompile'], 'expected string but got number')
-  CheckScriptFailure(['def Func(): void', 'return "a"', 'enddef', 'defcompile'], 'expected void but got string')
-  CheckScriptFailure(['def Func()', 'return "a"', 'enddef', 'defcompile'], 'expected void but got string')
+  CheckScriptFailure(['def Func(): void', 'return "a"', 'enddef', 'defcompile'], 'E1096: Returning a value in a function without a return type')
+  CheckScriptFailure(['def Func()', 'return "a"', 'enddef', 'defcompile'], 'E1096: Returning a value in a function without a return type')
 
   CheckScriptFailure(['def Func(): number', 'return', 'enddef', 'defcompile'], 'E1003:')
 

src/version.c

diff --git a/src/version.c b/src/version.c
index c94988f..8f85bb7 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1131,
+/**/
     1130,
 /**/
     1129,

src/vim9compile.c

diff --git a/src/vim9compile.c b/src/vim9compile.c
index b4209a1..e5a801a 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -4568,9 +4568,19 @@
 	stack_type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
 	if (set_return_type)
 	    cctx->ctx_ufunc->uf_ret_type = stack_type;
-	else if (need_type(stack_type, cctx->ctx_ufunc->uf_ret_type, -1, cctx)
+	else
+	{
+	    if (cctx->ctx_ufunc->uf_ret_type->tt_type == VAR_VOID
+		    && stack_type->tt_type != VAR_VOID
+		    && stack_type->tt_type != VAR_UNKNOWN)
+	    {
+		emsg(_("E1096: Returning a value in a function without a return type"));
+		return NULL;
+	    }
+	    if (need_type(stack_type, cctx->ctx_ufunc->uf_ret_type, -1, cctx)
 								       == FAIL)
 	    return NULL;
+	}
     }
     else
     {