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#![allow(clippy::single_element_loop, clippy::uninlined_format_args)]
#[macro_use]
mod macros;
use proc_macro2::{Delimiter, Group};
use quote::{quote, ToTokens as _};
use std::mem;
use syn::punctuated::Punctuated;
use syn::visit_mut::{self, VisitMut};
use syn::{parse_quote, token, Expr, ExprRange, ExprTuple, Stmt, Token};
#[test]
fn test_expr_parse() {
let tokens = quote!(..100u32);
snapshot!(tokens as Expr, @r###"
Expr::Range {
limits: RangeLimits::HalfOpen,
end: Some(Expr::Lit {
lit: 100u32,
}),
}
"###);
let tokens = quote!(..100u32);
snapshot!(tokens as ExprRange, @r###"
ExprRange {
limits: RangeLimits::HalfOpen,
end: Some(Expr::Lit {
lit: 100u32,
}),
}
"###);
}
#[test]
fn test_await() {
// Must not parse as Expr::Field.
let tokens = quote!(fut.await);
snapshot!(tokens as Expr, @r###"
Expr::Await {
base: Expr::Path {
path: Path {
segments: [
PathSegment {
ident: "fut",
},
],
},
},
}
"###);
}
#[rustfmt::skip]
#[test]
fn test_tuple_multi_index() {
let expected = snapshot!("tuple.0.0" as Expr, @r###"
Expr::Field {
base: Expr::Field {
base: Expr::Path {
path: Path {
segments: [
PathSegment {
ident: "tuple",
},
],
},
},
member: Member::Unnamed(Index {
index: 0,
}),
},
member: Member::Unnamed(Index {
index: 0,
}),
}
"###);
for &input in &[
"tuple .0.0",
"tuple. 0.0",
"tuple.0 .0",
"tuple.0. 0",
"tuple . 0 . 0",
] {
assert_eq!(expected, syn::parse_str(input).unwrap());
}
for tokens in [
quote!(tuple.0.0),
quote!(tuple .0.0),
quote!(tuple. 0.0),
quote!(tuple.0 .0),
quote!(tuple.0. 0),
quote!(tuple . 0 . 0),
] {
assert_eq!(expected, syn::parse2(tokens).unwrap());
}
}
#[test]
fn test_macro_variable_func() {
// mimics the token stream corresponding to `$fn()`
let path = Group::new(Delimiter::None, quote!(f));
let tokens = quote!(#path());
snapshot!(tokens as Expr, @r###"
Expr::Call {
func: Expr::Group {
expr: Expr::Path {
path: Path {
segments: [
PathSegment {
ident: "f",
},
],
},
},
},
}
"###);
let path = Group::new(Delimiter::None, quote! { #[inside] f });
let tokens = quote!(#[outside] #path());
snapshot!(tokens as Expr, @r###"
Expr::Call {
attrs: [
Attribute {
style: AttrStyle::Outer,
meta: Meta::Path {
segments: [
PathSegment {
ident: "outside",
},
],
},
},
],
func: Expr::Group {
expr: Expr::Path {
attrs: [
Attribute {
style: AttrStyle::Outer,
meta: Meta::Path {
segments: [
PathSegment {
ident: "inside",
},
],
},
},
],
path: Path {
segments: [
PathSegment {
ident: "f",
},
],
},
},
},
}
"###);
}
#[test]
fn test_macro_variable_macro() {
// mimics the token stream corresponding to `$macro!()`
let mac = Group::new(Delimiter::None, quote!(m));
let tokens = quote!(#mac!());
snapshot!(tokens as Expr, @r###"
Expr::Macro {
mac: Macro {
path: Path {
segments: [
PathSegment {
ident: "m",
},
],
},
delimiter: MacroDelimiter::Paren,
tokens: TokenStream(``),
},
}
"###);
}
#[test]
fn test_macro_variable_struct() {
// mimics the token stream corresponding to `$struct {}`
let s = Group::new(Delimiter::None, quote! { S });
let tokens = quote!(#s {});
snapshot!(tokens as Expr, @r###"
Expr::Struct {
path: Path {
segments: [
PathSegment {
ident: "S",
},
],
},
}
"###);
}
#[test]
fn test_macro_variable_unary() {
// mimics the token stream corresponding to `$expr.method()` where expr is `&self`
let inner = Group::new(Delimiter::None, quote!(&self));
let tokens = quote!(#inner.method());
snapshot!(tokens as Expr, @r###"
Expr::MethodCall {
receiver: Expr::Group {
expr: Expr::Reference {
expr: Expr::Path {
path: Path {
segments: [
PathSegment {
ident: "self",
},
],
},
},
},
},
method: "method",
}
"###);
}
#[test]
fn test_macro_variable_match_arm() {
// mimics the token stream corresponding to `match v { _ => $expr }`
let expr = Group::new(Delimiter::None, quote! { #[a] () });
let tokens = quote!(match v { _ => #expr });
snapshot!(tokens as Expr, @r###"
Expr::Match {
expr: Expr::Path {
path: Path {
segments: [
PathSegment {
ident: "v",
},
],
},
},
arms: [
Arm {
pat: Pat::Wild,
body: Expr::Group {
expr: Expr::Tuple {
attrs: [
Attribute {
style: AttrStyle::Outer,
meta: Meta::Path {
segments: [
PathSegment {
ident: "a",
},
],
},
},
],
},
},
},
],
}
"###);
let expr = Group::new(Delimiter::None, quote!(loop {} + 1));
let tokens = quote!(match v { _ => #expr });
snapshot!(tokens as Expr, @r###"
Expr::Match {
expr: Expr::Path {
path: Path {
segments: [
PathSegment {
ident: "v",
},
],
},
},
arms: [
Arm {
pat: Pat::Wild,
body: Expr::Group {
expr: Expr::Binary {
left: Expr::Loop {
body: Block {
stmts: [],
},
},
op: BinOp::Add,
right: Expr::Lit {
lit: 1,
},
},
},
},
],
}
"###);
}
#[test]
fn test_closure_vs_rangefull() {
let tokens = quote!(|| .. .method());
snapshot!(tokens as Expr, @r###"
Expr::MethodCall {
receiver: Expr::Closure {
output: ReturnType::Default,
body: Expr::Range {
limits: RangeLimits::HalfOpen,
},
},
method: "method",
}
"###);
}
#[test]
fn test_postfix_operator_after_cast() {
syn::parse_str::<Expr>("|| &x as T[0]").unwrap_err();
syn::parse_str::<Expr>("|| () as ()()").unwrap_err();
}
#[test]
fn test_range_kinds() {
syn::parse_str::<Expr>("..").unwrap();
syn::parse_str::<Expr>("..hi").unwrap();
syn::parse_str::<Expr>("lo..").unwrap();
syn::parse_str::<Expr>("lo..hi").unwrap();
syn::parse_str::<Expr>("..=").unwrap_err();
syn::parse_str::<Expr>("..=hi").unwrap();
syn::parse_str::<Expr>("lo..=").unwrap_err();
syn::parse_str::<Expr>("lo..=hi").unwrap();
syn::parse_str::<Expr>("...").unwrap_err();
syn::parse_str::<Expr>("...hi").unwrap_err();
syn::parse_str::<Expr>("lo...").unwrap_err();
syn::parse_str::<Expr>("lo...hi").unwrap_err();
}
#[test]
fn test_range_precedence() {
snapshot!(".. .." as Expr, @r###"
Expr::Range {
limits: RangeLimits::HalfOpen,
end: Some(Expr::Range {
limits: RangeLimits::HalfOpen,
}),
}
"###);
snapshot!(".. .. ()" as Expr, @r###"
Expr::Range {
limits: RangeLimits::HalfOpen,
end: Some(Expr::Range {
limits: RangeLimits::HalfOpen,
end: Some(Expr::Tuple),
}),
}
"###);
snapshot!("() .. .." as Expr, @r###"
Expr::Range {
start: Some(Expr::Tuple),
limits: RangeLimits::HalfOpen,
end: Some(Expr::Range {
limits: RangeLimits::HalfOpen,
}),
}
"###);
// A range with a lower bound cannot be the upper bound of another range,
// and a range with an upper bound cannot be the lower bound of another
// range.
syn::parse_str::<Expr>(".. x ..").unwrap_err();
syn::parse_str::<Expr>("x .. x ..").unwrap_err();
}
#[test]
fn test_ambiguous_label() {
for stmt in [
quote! {
return 'label: loop { break 'label 42; };
},
quote! {
break ('label: loop { break 'label 42; });
},
quote! {
break 1 + 'label: loop { break 'label 42; };
},
quote! {
break 'outer 'inner: loop { break 'inner 42; };
},
] {
syn::parse2::<Stmt>(stmt).unwrap();
}
for stmt in [
quote! {
break 'label: loop { break 'label 42; };
},
] {
syn::parse2::<Stmt>(stmt).unwrap_err();
}
}
#[test]
fn test_extended_interpolated_path() {
let path = Group::new(Delimiter::None, quote!(a::b));
let tokens = quote!(if #path {});
snapshot!(tokens as Expr, @r###"
Expr::If {
cond: Expr::Group {
expr: Expr::Path {
path: Path {
segments: [
PathSegment {
ident: "a",
},
Token![::],
PathSegment {
ident: "b",
},
],
},
},
},
then_branch: Block {
stmts: [],
},
}
"###);
let tokens = quote!(#path {});
snapshot!(tokens as Expr, @r###"
Expr::Struct {
path: Path {
segments: [
PathSegment {
ident: "a",
},
Token![::],
PathSegment {
ident: "b",
},
],
},
}
"###);
let tokens = quote!(#path :: c);
snapshot!(tokens as Expr, @r###"
Expr::Path {
path: Path {
segments: [
PathSegment {
ident: "a",
},
Token![::],
PathSegment {
ident: "b",
},
Token![::],
PathSegment {
ident: "c",
},
],
},
}
"###);
let nested = Group::new(Delimiter::None, quote!(a::b || true));
let tokens = quote!(if #nested && false {});
snapshot!(tokens as Expr, @r###"
Expr::If {
cond: Expr::Binary {
left: Expr::Group {
expr: Expr::Binary {
left: Expr::Path {
path: Path {
segments: [
PathSegment {
ident: "a",
},
Token![::],
PathSegment {
ident: "b",
},
],
},
},
op: BinOp::Or,
right: Expr::Lit {
lit: Lit::Bool {
value: true,
},
},
},
},
op: BinOp::And,
right: Expr::Lit {
lit: Lit::Bool {
value: false,
},
},
},
then_branch: Block {
stmts: [],
},
}
"###);
}
#[test]
fn test_tuple_comma() {
let mut expr = ExprTuple {
attrs: Vec::new(),
paren_token: token::Paren::default(),
elems: Punctuated::new(),
};
snapshot!(expr.to_token_stream() as Expr, @"Expr::Tuple");
expr.elems.push_value(parse_quote!(continue));
// Must not parse to Expr::Paren
snapshot!(expr.to_token_stream() as Expr, @r###"
Expr::Tuple {
elems: [
Expr::Continue,
Token![,],
],
}
"###);
expr.elems.push_punct(<Token![,]>::default());
snapshot!(expr.to_token_stream() as Expr, @r###"
Expr::Tuple {
elems: [
Expr::Continue,
Token![,],
],
}
"###);
expr.elems.push_value(parse_quote!(continue));
snapshot!(expr.to_token_stream() as Expr, @r###"
Expr::Tuple {
elems: [
Expr::Continue,
Token![,],
Expr::Continue,
],
}
"###);
expr.elems.push_punct(<Token![,]>::default());
snapshot!(expr.to_token_stream() as Expr, @r###"
Expr::Tuple {
elems: [
Expr::Continue,
Token![,],
Expr::Continue,
Token![,],
],
}
"###);
}
#[test]
fn test_binop_associativity() {
// Left to right.
snapshot!("() + () + ()" as Expr, @r###"
Expr::Binary {
left: Expr::Binary {
left: Expr::Tuple,
op: BinOp::Add,
right: Expr::Tuple,
},
op: BinOp::Add,
right: Expr::Tuple,
}
"###);
// Right to left.
snapshot!("() += () += ()" as Expr, @r###"
Expr::Binary {
left: Expr::Tuple,
op: BinOp::AddAssign,
right: Expr::Binary {
left: Expr::Tuple,
op: BinOp::AddAssign,
right: Expr::Tuple,
},
}
"###);
// Parenthesization is required.
syn::parse_str::<Expr>("() == () == ()").unwrap_err();
}
#[test]
fn test_assign_range_precedence() {
// Range has higher precedence as the right-hand of an assignment, but
// ambiguous precedence as the left-hand of an assignment.
snapshot!("() = () .. ()" as Expr, @r###"
Expr::Assign {
left: Expr::Tuple,
right: Expr::Range {
start: Some(Expr::Tuple),
limits: RangeLimits::HalfOpen,
end: Some(Expr::Tuple),
},
}
"###);
snapshot!("() += () .. ()" as Expr, @r###"
Expr::Binary {
left: Expr::Tuple,
op: BinOp::AddAssign,
right: Expr::Range {
start: Some(Expr::Tuple),
limits: RangeLimits::HalfOpen,
end: Some(Expr::Tuple),
},
}
"###);
syn::parse_str::<Expr>("() .. () = ()").unwrap_err();
syn::parse_str::<Expr>("() .. () += ()").unwrap_err();
}
#[test]
fn test_fixup() {
struct FlattenParens;
impl VisitMut for FlattenParens {
fn visit_expr_mut(&mut self, e: &mut Expr) {
while let Expr::Paren(paren) = e {
*e = mem::replace(&mut *paren.expr, Expr::PLACEHOLDER);
}
visit_mut::visit_expr_mut(self, e);
}
}
for tokens in [
quote! { 2 * (1 + 1) },
quote! { 0 + (0 + 0) },
quote! { (a = b) = c },
quote! { (x as i32) < 0 },
quote! { (1 + x as i32) < 0 },
quote! { (1 + 1).abs() },
quote! { (lo..hi)[..] },
quote! { (a..b)..(c..d) },
quote! { (&mut fut).await },
quote! { &mut (x as i32) },
quote! { -(x as i32) },
quote! { if (S {} == 1) {} },
quote! { { (m! {}) - 1 } },
quote! { match m { _ => ({}) - 1 } },
quote! { if let _ = (a && b) && c {} },
quote! { if let _ = (S {}) {} },
] {
let original: Expr = syn::parse2(tokens).unwrap();
let mut flat = original.clone();
FlattenParens.visit_expr_mut(&mut flat);
let reconstructed: Expr = match syn::parse2(flat.to_token_stream()) {
Ok(reconstructed) => reconstructed,
Err(err) => panic!("failed to parse `{}`: {}", flat.to_token_stream(), err),
};
assert!(
original == reconstructed,
"original: {}\nreconstructed: {}",
original.to_token_stream(),
reconstructed.to_token_stream(),
);
}
}