patch 8.2.2395: Vim9: error for wrong type may report wrong line number

Problem:    Vim9: error for wrong type may report wrong line number.
Solution:   Save and restore the line number when evaluating the expression.
            (closes #7727)
diff --git a/src/evalvars.c b/src/evalvars.c
index dfc8e63..b6a6927 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -838,6 +838,8 @@
 	i = FAIL;
 	if (has_assign || concat)
 	{
+	    int cur_lnum;
+
 	    op[0] = '=';
 	    op[1] = NUL;
 	    if (*expr != '=')
@@ -882,10 +884,15 @@
 		evalarg.eval_cookie = eap->cookie;
 	    }
 	    expr = skipwhite_and_linebreak(expr, &evalarg);
+	    cur_lnum = SOURCING_LNUM;
 	    i = eval0(expr, &rettv, eap, &evalarg);
 	    if (eap->skip)
 		--emsg_skip;
 	    clear_evalarg(&evalarg, eap);
+
+	    // Restore the line number so that any type error is given for the
+	    // declaration, not the expression.
+	    SOURCING_LNUM = cur_lnum;
 	}
 	if (eap->skip)
 	{