Replace STD to CORE lib

.github/workflows/ci.yml

@@ -105,6 +105,10 @@ jobs:
       - run: cargo +nightly llvm-cov --workspace --branch --exclude-from-report pastey-test-suite --doctests --lcov --output-path lcov.info
         env:
           RUSTFLAGS: -C instrument-coverage -C llvm-args=-pgo-warn-missing-function
+      - name: Print coverage summary and thresould check
+        run: cargo +nightly llvm-cov --workspace --branch --exclude-from-report pastey-test-suite --doctests --fail-under-lines 100 --fail-under-regions 100
+        env:
+          RUSTFLAGS: -C instrument-coverage -C llvm-args=-pgo-warn-missing-function
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v5
         with:

src/attr.rs

@@ -1,9 +1,9 @@
 use crate::error::Result;
 use crate::segment::{self, Segment};
+use core::iter;
+use core::mem;
+use core::str::FromStr;
 use proc_macro::{Delimiter, Group, Spacing, Span, TokenStream, TokenTree};
-use std::iter;
-use std::mem;
-use std::str::FromStr;
 
 pub fn expand_attr(
     attr: TokenStream,

src/error.rs

@@ -1,7 +1,7 @@
+use core::iter::FromIterator;
 use proc_macro::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
-use std::iter::FromIterator;
 
-pub type Result<T> = std::result::Result<T, Error>;
+pub type Result<T> = core::result::Result<T, Error>;
 
 pub struct Error {
     begin: Span,

src/lib.rs

@@ -20,13 +20,13 @@ mod test_helpers;
 use crate::attr::expand_attr;
 use crate::error::{Error, Result};
 use crate::segment::Segment;
+use core::char;
+use core::iter;
+use core::str::FromStr;
 use proc_macro::{
     Delimiter, Group, Ident, LexError, Literal, Punct, Spacing, Span, TokenStream, TokenTree,
 };
-use std::char;
-use std::iter;
 use std::panic;
-use std::str::FromStr;
 
 #[proc_macro]
 pub fn paste(input: TokenStream) -> TokenStream {

src/segment.rs

@@ -1,6 +1,6 @@
 use crate::error::{Error, Result};
+use core::iter::Peekable;
 use proc_macro::{token_stream, Delimiter, Group, Ident, Literal, Span, TokenTree};
-use std::iter::Peekable;
 
 pub(crate) enum Segment {
     String(LitStr),

src/test_helpers.rs

@@ -5,8 +5,8 @@
 // not production code.
 
 use crate::attr::expand_attr;
+use core::str::FromStr;
 use proc_macro::{Delimiter, Group, Ident, Punct, Spacing, Span, TokenStream, TokenTree};
-use std::str::FromStr;
 
 use super::{expand, parse_bracket_as_segments, pasted_to_tokens};