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Diffstat (limited to '')
| -rw-r--r-- | dhall/src/syntax/ast/span.rs | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/dhall/src/syntax/ast/span.rs b/dhall/src/syntax/ast/span.rs index 79bcc52..2e09863 100644 --- a/dhall/src/syntax/ast/span.rs +++ b/dhall/src/syntax/ast/span.rs @@ -75,13 +75,15 @@ impl Span { } /// Convert a byte idx into a string into a char idx for consumption by annotate_snippets. +/// The byte idx must be at a char boundary. fn char_idx_from_byte_idx(input: &str, idx: usize) -> usize { + use std::iter::once; input .char_indices() + .map(|(byte_i, _)| byte_i) // We don't care about the char + .chain(once(input.len())) // In case the idx points to the end of the string .enumerate() - .find(|(_, (i, _))| *i == idx) - .map(|(i, (_, _))| i) - // We should be able to unwrap() here, but somehow it panics on an example from - // serde_dhall/lib.rs... - .unwrap_or(0) + .find(|(_, byte_i)| *byte_i == idx) + .map(|(char_i, _)| char_i) + .unwrap() } |