v.parser: show better position for sort struct init warning (#10939)

vlib/v/checker/tests/struct_short_init_warning.out

@@ -0,0 +1,13 @@
+vlib/v/checker/tests/struct_short_init_warning.vv:6:9: warning: short struct initalization is deprecated, use explicit struct name
+    4 |
+    5 | fn f(foo Foo) Foo {
+    6 |     return {v: foo.v}
+      |            ~~~~~~~~~~
+    7 | }
+    8 |
+vlib/v/checker/tests/struct_short_init_warning.vv:10:4: warning: short struct initalization is deprecated, use explicit struct name
+    8 |
+    9 | fn main() {
+   10 |     f({v: 10})
+      |       ~~~~~~~
+   11 | }

vlib/v/checker/tests/struct_short_init_warning.vv

@@ -0,0 +1,11 @@
+struct Foo {
+	v int
+}
+
+fn f(foo Foo) Foo {
+	return {v: foo.v}
+}
+
+fn main() {
+	f({v: 10})
+}

vlib/v/parser/expr.v

@@ -312,9 +312,9 @@ pub fn (mut p Parser) check_expr(precedence int) ?ast.Expr {
 					node = p.assoc()
 				} else if (p.tok.kind == .name && p.peek_tok.kind == .colon)
 					|| p.tok.kind in [.rcbr, .comment, .ellipsis] {
-					p.warn_with_pos('short struct initalization is deprecated, use explicit struct name',
-						p.prev_tok.position())
 					node = p.struct_init(true) // short_syntax: true
+					p.warn_with_pos('short struct initalization is deprecated, use explicit struct name',
+						node.position())
 				} else if p.tok.kind == .name {
 					p.next()
 					return p.error_with_pos('unexpected $p.tok, expecting `:` after struct field name',

vlib/v/parser/struct.v

@@ -329,7 +329,7 @@ fn (mut p Parser) struct_decl() ast.StructDecl {
 }
 
 fn (mut p Parser) struct_init(short_syntax bool) ast.StructInit {
-	first_pos := p.tok.position()
+	first_pos := (if short_syntax && p.prev_tok.kind == .lcbr { p.prev_tok } else { p.tok }).position()
 	typ := if short_syntax { ast.void_type } else { p.parse_type() }
 	p.expr_mod = ''
 	// sym := p.table.get_type_symbol(typ)