xref: /third_party/rust/crates/syn/tests/test_pat.rs (revision fad3a1d3) 
1#![allow(clippy::uninlined_format_args)]
2
3#[macro_use]
4mod macros;
5
6use proc_macro2::{Delimiter, Group, TokenStream, TokenTree};
7use quote::{quote, ToTokens as _};
8use syn::parse::Parser;
9use syn::punctuated::Punctuated;
10use syn::{parse_quote, token, Item, Pat, PatTuple, Stmt, Token};
11
12#[test]
13fn test_pat_ident() {
14    match Pat::parse_single.parse2(quote!(self)).unwrap() {
15        Pat::Ident(_) => (),
16        value => panic!("expected PatIdent, got {:?}", value),
17    }
18}
19
20#[test]
21fn test_pat_path() {
22    match Pat::parse_single.parse2(quote!(self::CONST)).unwrap() {
23        Pat::Path(_) => (),
24        value => panic!("expected PatPath, got {:?}", value),
25    }
26}
27
28#[test]
29fn test_leading_vert() {
30    // https://github.com/rust-lang/rust/blob/1.43.0/src/test/ui/or-patterns/remove-leading-vert.rs
31
32    syn::parse_str::<Item>("fn f() {}").unwrap();
33    syn::parse_str::<Item>("fn fun1(| A: E) {}").unwrap_err();
34    syn::parse_str::<Item>("fn fun2(|| A: E) {}").unwrap_err();
35
36    syn::parse_str::<Stmt>("let | () = ();").unwrap_err();
37    syn::parse_str::<Stmt>("let (| A): E;").unwrap();
38    syn::parse_str::<Stmt>("let (|| A): (E);").unwrap_err();
39    syn::parse_str::<Stmt>("let (| A,): (E,);").unwrap();
40    syn::parse_str::<Stmt>("let [| A]: [E; 1];").unwrap();
41    syn::parse_str::<Stmt>("let [|| A]: [E; 1];").unwrap_err();
42    syn::parse_str::<Stmt>("let TS(| A): TS;").unwrap();
43    syn::parse_str::<Stmt>("let TS(|| A): TS;").unwrap_err();
44    syn::parse_str::<Stmt>("let NS { f: | A }: NS;").unwrap();
45    syn::parse_str::<Stmt>("let NS { f: || A }: NS;").unwrap_err();
46}
47
48#[test]
49fn test_group() {
50    let group = Group::new(Delimiter::None, quote!(Some(_)));
51    let tokens = TokenStream::from_iter(vec![TokenTree::Group(group)]);
52    let pat = Pat::parse_single.parse2(tokens).unwrap();
53
54    snapshot!(pat, @r###"
55    Pat::TupleStruct {
56        path: Path {
57            segments: [
58                PathSegment {
59                    ident: "Some",
60                },
61            ],
62        },
63        elems: [
64            Pat::Wild,
65        ],
66    }
67    "###);
68}
69
70#[test]
71fn test_ranges() {
72    Pat::parse_single.parse_str("..").unwrap();
73    Pat::parse_single.parse_str("..hi").unwrap();
74    Pat::parse_single.parse_str("lo..").unwrap();
75    Pat::parse_single.parse_str("lo..hi").unwrap();
76
77    Pat::parse_single.parse_str("..=").unwrap_err();
78    Pat::parse_single.parse_str("..=hi").unwrap();
79    Pat::parse_single.parse_str("lo..=").unwrap_err();
80    Pat::parse_single.parse_str("lo..=hi").unwrap();
81
82    Pat::parse_single.parse_str("...").unwrap_err();
83    Pat::parse_single.parse_str("...hi").unwrap_err();
84    Pat::parse_single.parse_str("lo...").unwrap_err();
85    Pat::parse_single.parse_str("lo...hi").unwrap();
86
87    Pat::parse_single.parse_str("[lo..]").unwrap_err();
88    Pat::parse_single.parse_str("[..=hi]").unwrap_err();
89    Pat::parse_single.parse_str("[(lo..)]").unwrap();
90    Pat::parse_single.parse_str("[(..=hi)]").unwrap();
91    Pat::parse_single.parse_str("[lo..=hi]").unwrap();
92
93    Pat::parse_single.parse_str("[_, lo.., _]").unwrap_err();
94    Pat::parse_single.parse_str("[_, ..=hi, _]").unwrap_err();
95    Pat::parse_single.parse_str("[_, (lo..), _]").unwrap();
96    Pat::parse_single.parse_str("[_, (..=hi), _]").unwrap();
97    Pat::parse_single.parse_str("[_, lo..=hi, _]").unwrap();
98}
99
100#[test]
101fn test_tuple_comma() {
102    let mut expr = PatTuple {
103        attrs: Vec::new(),
104        paren_token: token::Paren::default(),
105        elems: Punctuated::new(),
106    };
107    snapshot!(expr.to_token_stream() as Pat, @"Pat::Tuple");
108
109    expr.elems.push_value(parse_quote!(_));
110    // Must not parse to Pat::Paren
111    snapshot!(expr.to_token_stream() as Pat, @r###"
112    Pat::Tuple {
113        elems: [
114            Pat::Wild,
115            Token![,],
116        ],
117    }
118    "###);
119
120    expr.elems.push_punct(<Token![,]>::default());
121    snapshot!(expr.to_token_stream() as Pat, @r###"
122    Pat::Tuple {
123        elems: [
124            Pat::Wild,
125            Token![,],
126        ],
127    }
128    "###);
129
130    expr.elems.push_value(parse_quote!(_));
131    snapshot!(expr.to_token_stream() as Pat, @r###"
132    Pat::Tuple {
133        elems: [
134            Pat::Wild,
135            Token![,],
136            Pat::Wild,
137        ],
138    }
139    "###);
140
141    expr.elems.push_punct(<Token![,]>::default());
142    snapshot!(expr.to_token_stream() as Pat, @r###"
143    Pat::Tuple {
144        elems: [
145            Pat::Wild,
146            Token![,],
147            Pat::Wild,
148            Token![,],
149        ],
150    }
151    "###);
152}
153