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authorFlorian Diebold <[email protected]>2019-04-28 14:43:10 +0100
committerFlorian Diebold <[email protected]>2019-04-28 15:03:49 +0100
commit85633656dfc3ad4516a99e3062599e3ee85a578d (patch)
tree6b037199384ddf1021c2ad81886425dfcb8271a8 /crates/ra_syntax/src
parent1dd3d9bc2d328e164c594f3d2022dcf174f907a9 (diff)
Fix hover on the beginning of a nested expression
E.g. in ``` let foo = 1u32; if true { <|>foo; } ``` the hover shows `()`, the type of the whole if expression, instead of the more sensible `u32`. The reason for this was that the search for an expression was slightly left-biased: When on the edge between two tokens, it first looked at all ancestors of the left token and then of the right token. Instead merge the ancestors in ascending order, so that we get the smaller of the two possible expressions.
Diffstat (limited to 'crates/ra_syntax/src')
-rw-r--r--crates/ra_syntax/src/algo.rs21
1 files changed, 18 insertions, 3 deletions
diff --git a/crates/ra_syntax/src/algo.rs b/crates/ra_syntax/src/algo.rs
index 1f68fe467..d31d00343 100644
--- a/crates/ra_syntax/src/algo.rs
+++ b/crates/ra_syntax/src/algo.rs
@@ -1,5 +1,7 @@
1pub mod visit; 1pub mod visit;
2 2
3use itertools::Itertools;
4
3use crate::{SyntaxNode, TextRange, TextUnit, AstNode, Direction, SyntaxToken, SyntaxElement}; 5use crate::{SyntaxNode, TextRange, TextUnit, AstNode, Direction, SyntaxToken, SyntaxElement};
4 6
5pub use rowan::TokenAtOffset; 7pub use rowan::TokenAtOffset;
@@ -12,6 +14,20 @@ pub fn find_token_at_offset(node: &SyntaxNode, offset: TextUnit) -> TokenAtOffse
12 } 14 }
13} 15}
14 16
17/// Returns ancestors of the node at the offset, sorted by length. This should
18/// do the right thing at an edge, e.g. when searching for expressions at `{
19/// <|>foo }` we will get the name reference instead of the whole block, which
20/// we would get if we just did `find_token_at_offset(...).flat_map(|t|
21/// t.parent().ancestors())`.
22pub fn ancestors_at_offset(
23 node: &SyntaxNode,
24 offset: TextUnit,
25) -> impl Iterator<Item = &SyntaxNode> {
26 find_token_at_offset(node, offset)
27 .map(|token| token.parent().ancestors())
28 .kmerge_by(|node1, node2| node1.range().len() < node2.range().len())
29}
30
15/// Finds a node of specific Ast type at offset. Note that this is slightly 31/// Finds a node of specific Ast type at offset. Note that this is slightly
16/// imprecise: if the cursor is strictly between two nodes of the desired type, 32/// imprecise: if the cursor is strictly between two nodes of the desired type,
17/// as in 33/// as in
@@ -20,10 +36,9 @@ pub fn find_token_at_offset(node: &SyntaxNode, offset: TextUnit) -> TokenAtOffse
20/// struct Foo {}|struct Bar; 36/// struct Foo {}|struct Bar;
21/// ``` 37/// ```
22/// 38///
23/// then the left node will be silently preferred. 39/// then the shorter node will be silently preferred.
24pub fn find_node_at_offset<N: AstNode>(syntax: &SyntaxNode, offset: TextUnit) -> Option<&N> { 40pub fn find_node_at_offset<N: AstNode>(syntax: &SyntaxNode, offset: TextUnit) -> Option<&N> {
25 find_token_at_offset(syntax, offset) 41 ancestors_at_offset(syntax, offset).find_map(N::cast)
26 .find_map(|leaf| leaf.parent().ancestors().find_map(N::cast))
27} 42}
28 43
29/// Finds the first sibling in the given direction which is not `trivia` 44/// Finds the first sibling in the given direction which is not `trivia`