bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Rollup merge of #83489 - LeSeulArtichaut:deref-else, r=davidtwco

Browse source 
Properly suggest deref in else block

Continues #79755, fixes #79736
r? `@davidtwco`
This commit is contained in:
Yuki Okushi 2021-04-06 06:24:09 +09:00 • committed by GitHub
commit d9f123a5ae
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
3 changed files with 92 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

28
compiler/rustc_typeck/src/check/demand.rs
View file

@ -366,6 +366,29 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
false
}
/// If the given `HirId` corresponds to a block with a trailing expression, return that expression
crate fn maybe_get_block_expr(&self, hir_id: hir::HirId) -> Option<&'tcx hir::Expr<'tcx>> {
match self.tcx.hir().find(hir_id)? {
Node::Expr(hir::Expr { kind: hir::ExprKind::Block(block, ..), .. }) => block.expr,
_ => None,
}
}
/// Returns whether the given expression is an `else if`.
crate fn is_else_if_block(&self, expr: &hir::Expr<'_>) -> bool {
if let hir::ExprKind::If(..) = expr.kind {
let parent_id = self.tcx.hir().get_parent_node(expr.hir_id);
if let Some(Node::Expr(hir::Expr {
kind: hir::ExprKind::If(_, _, Some(else_expr)),
..
})) = self.tcx.hir().find(parent_id)
{
return else_expr.hir_id == expr.hir_id;
}
}
false
}
/// This function is used to determine potential "simple" improvements or users' errors and
/// provide them useful help. For example:
///
@ -652,6 +675,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
};
let suggestion = if is_struct_pat_shorthand_field {
format!("{}: *{}", code, code)
} else if self.is_else_if_block(expr) {
// Don't suggest nonsense like `else *if`
return None;
} else if let Some(expr) = self.maybe_get_block_expr(expr.hir_id) {
format!("*{}", sm.span_to_snippet(expr.span).unwrap_or(code))
} else {
format!("*{}", code)
};