1fc6dbc32b
Add inline const and other possible curly brace expressions to expr_trailing_brace Add tests for `}` before `else` in `let...else` error Change to explicit cases for expressions with optional values when being checked for trailing braces Add tests for more complex cases of `}` before `else` in `let..else` statement Move other possible `}` cases into separate arm and add FIXME for future reference
84 lines
2.5 KiB
Rust
84 lines
2.5 KiB
Rust
//! Routines the parser uses to classify AST nodes
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// Predicates on exprs and stmts that the pretty-printer and parser use
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use crate::ast;
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/// Does this expression require a semicolon to be treated
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/// as a statement? The negation of this: 'can this expression
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/// be used as a statement without a semicolon' -- is used
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/// as an early-bail-out in the parser so that, for instance,
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/// if true {...} else {...}
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/// |x| 5
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/// isn't parsed as (if true {...} else {...} | x) | 5
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pub fn expr_requires_semi_to_be_stmt(e: &ast::Expr) -> bool {
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!matches!(
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e.kind,
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ast::ExprKind::If(..)
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| ast::ExprKind::Match(..)
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| ast::ExprKind::Block(..)
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| ast::ExprKind::While(..)
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| ast::ExprKind::Loop(..)
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| ast::ExprKind::ForLoop(..)
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| ast::ExprKind::TryBlock(..)
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| ast::ExprKind::ConstBlock(..)
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)
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}
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/// If an expression ends with `}`, returns the innermost expression ending in the `}`
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pub fn expr_trailing_brace(mut expr: &ast::Expr) -> Option<&ast::Expr> {
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use ast::ExprKind::*;
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loop {
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match &expr.kind {
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AddrOf(_, _, e)
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| Assign(_, e, _)
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| AssignOp(_, _, e)
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| Binary(_, _, e)
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| Break(_, Some(e))
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| Let(_, e, _, _)
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| Range(_, Some(e), _)
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| Ret(Some(e))
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| Unary(_, e)
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| Yield(Some(e))
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| Yeet(Some(e))
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| Become(e) => {
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expr = e;
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}
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Closure(closure) => {
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expr = &closure.body;
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}
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Gen(..) | Block(..) | ForLoop(..) | If(..) | Loop(..) | Match(..) | Struct(..)
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| TryBlock(..) | While(..) | ConstBlock(_) => break Some(expr),
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// FIXME: These can end in `}`, but changing these would break stable code.
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InlineAsm(_) | OffsetOf(_, _) | MacCall(_) | IncludedBytes(_) | FormatArgs(_) => {
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break None;
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}
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Break(_, None)
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| Range(_, None, _)
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| Ret(None)
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| Yield(None)
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| Array(_)
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| Call(_, _)
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| MethodCall(_)
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| Tup(_)
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| Lit(_)
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| Cast(_, _)
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| Type(_, _)
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| Await(_, _)
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| Field(_, _)
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| Index(_, _, _)
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| Underscore
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| Path(_, _)
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| Continue(_)
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| Repeat(_, _)
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| Paren(_)
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| Try(_)
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| Yeet(None)
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| Err => break None,
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}
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}
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}
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