1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185

use crate::algorithm::Printer;
use crate::iter::IterDelimited;
use crate::INDENT;
use syn::{
    AngleBracketedGenericArguments, Binding, Constraint, Expr, GenericArgument,
    ParenthesizedGenericArguments, Path, PathArguments, PathSegment, QSelf,
};

impl Printer {
    pub fn path(&mut self, path: &Path) {
        assert!(!path.segments.is_empty());
        for segment in path.segments.iter().delimited() {
            if !segment.is_first || path.leading_colon.is_some() {
                self.word("::");
            }
            self.path_segment(&segment);
        }
    }

    pub fn path_segment(&mut self, segment: &PathSegment) {
        self.ident(&segment.ident);
        self.path_arguments(&segment.arguments);
    }

    fn path_arguments(&mut self, arguments: &PathArguments) {
        match arguments {
            PathArguments::None => {}
            PathArguments::AngleBracketed(arguments) => {
                self.angle_bracketed_generic_arguments(arguments);
            }
            PathArguments::Parenthesized(arguments) => {
                self.parenthesized_generic_arguments(arguments);
            }
        }
    }

    fn generic_argument(&mut self, arg: &GenericArgument) {
        match arg {
            GenericArgument::Lifetime(lifetime) => self.lifetime(lifetime),
            GenericArgument::Type(ty) => self.ty(ty),
            GenericArgument::Binding(binding) => self.binding(binding),
            GenericArgument::Constraint(constraint) => self.constraint(constraint),
            GenericArgument::Const(expr) => {
                match expr {
                    Expr::Lit(expr) => self.expr_lit(expr),
                    Expr::Block(expr) => self.expr_block(expr),
                    // ERROR CORRECTION: Add braces to make sure that the
                    // generated code is valid.
                    _ => {
                        self.word("{");
                        self.expr(expr);
                        self.word("}");
                    }
                }
            }
        }
    }

    fn angle_bracketed_generic_arguments(&mut self, generic: &AngleBracketedGenericArguments) {
        if generic.args.is_empty() {
            return;
        }

        if generic.colon2_token.is_some() {
            self.word("::");
        }
        self.word("<");
        self.cbox(INDENT);
        self.zerobreak();

        // Print lifetimes before types and consts, all before bindings,
        // regardless of their order in self.args.
        //
        // TODO: ordering rules for const arguments vs type arguments have
        // not been settled yet. https://github.com/rust-lang/rust/issues/44580
        for arg in generic.args.iter().delimited() {
            match *arg {
                GenericArgument::Lifetime(_) => {
                    self.generic_argument(&arg);
                    self.trailing_comma(arg.is_last);
                }
                GenericArgument::Type(_)
                | GenericArgument::Binding(_)
                | GenericArgument::Constraint(_)
                | GenericArgument::Const(_) => {}
            }
        }
        for arg in generic.args.iter().delimited() {
            match *arg {
                GenericArgument::Type(_) | GenericArgument::Const(_) => {
                    self.generic_argument(&arg);
                    self.trailing_comma(arg.is_last);
                }
                GenericArgument::Lifetime(_)
                | GenericArgument::Binding(_)
                | GenericArgument::Constraint(_) => {}
            }
        }
        for arg in generic.args.iter().delimited() {
            match *arg {
                GenericArgument::Binding(_) | GenericArgument::Constraint(_) => {
                    self.generic_argument(&arg);
                    self.trailing_comma(arg.is_last);
                }
                GenericArgument::Lifetime(_)
                | GenericArgument::Type(_)
                | GenericArgument::Const(_) => {}
            }
        }

        self.offset(-INDENT);
        self.end();
        self.word(">");
    }

    fn binding(&mut self, binding: &Binding) {
        self.ident(&binding.ident);
        self.word(" = ");
        self.ty(&binding.ty);
    }

    fn constraint(&mut self, constraint: &Constraint) {
        self.ident(&constraint.ident);
        self.ibox(INDENT);
        for bound in constraint.bounds.iter().delimited() {
            if bound.is_first {
                self.word(": ");
            } else {
                self.space();
                self.word("+ ");
            }
            self.type_param_bound(&bound);
        }
        self.end();
    }

    fn parenthesized_generic_arguments(&mut self, arguments: &ParenthesizedGenericArguments) {
        self.cbox(INDENT);
        self.word("(");
        self.zerobreak();
        for ty in arguments.inputs.iter().delimited() {
            self.ty(&ty);
            self.trailing_comma(ty.is_last);
        }
        self.offset(-INDENT);
        self.word(")");
        self.return_type(&arguments.output);
        self.end();
    }

    pub fn qpath(&mut self, qself: &Option<QSelf>, path: &Path) {
        let qself = match qself {
            Some(qself) => qself,
            None => {
                self.path(path);
                return;
            }
        };

        assert!(qself.position < path.segments.len());

        self.word("<");
        self.ty(&qself.ty);

        let mut segments = path.segments.iter();
        if qself.position > 0 {
            self.word(" as ");
            for segment in segments.by_ref().take(qself.position).delimited() {
                if !segment.is_first || path.leading_colon.is_some() {
                    self.word("::");
                }
                self.path_segment(&segment);
                if segment.is_last {
                    self.word(">");
                }
            }
        } else {
            self.word(">");
        }
        for segment in segments {
            self.word("::");
            self.path_segment(segment);
        }
    }
}