Merge #6111

6111: Add assist for converting the base of integer literals. r=SomeoneToIgnore a=vlakreeh

This PR adds an assist similar to Intellij's [convert number to](https://i.imgur.com/JH6wstP.png). It also does a small refactor to [assists/src/tests.rs](https://github.com/rust-analyzer/rust-analyzer/blob/fc34403018079ea053f26d0a31b7517053c7dd8c/crates/assists/src/tests.rs) to add the ability to specify the resolved assist for a specific action within an assist group.

## Demo
![Demo of the assist in action](https://i.imgur.com/MBhdPFH.gif)

Co-authored-by: vlakreeh <[email protected]>

1 files changed, 701 insertions, 0 deletions

diff --git a/crates/assists/src/handlers/convert_integer_literal.rs b/crates/assists/src/handlers/convert_integer_literal.rs
new file mode 100644
index 000000000..ea35e833a
--- /dev/null
+++ b/crates/assists/src/handlers/convert_integer_literal.rs
@@ -0,0 +1,701 @@
+use syntax::{ast, AstNode, SmolStr};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists, GroupLabel};
+
+// Assist: convert_integer_literal
+//
+// Converts the base of integer literals to other bases.
+//
+// ```
+// const _: i32 = 10<|>;
+// ```
+// ->
+// ```
+// const _: i32 = 0b1010;
+// ```
+pub(crate) fn convert_integer_literal(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let literal = ctx.find_node_at_offset::<ast::Literal>()?;
+    let range = literal.syntax().text_range();
+    let group_id = GroupLabel("Convert integer base".into());
+
+    let suffix = match literal.kind() {
+        ast::LiteralKind::IntNumber { suffix } => suffix,
+        _ => return None,
+    };
+    let suffix_len = suffix.as_ref().map(|s| s.len()).unwrap_or(0);
+    let raw_literal_text = literal.syntax().to_string();
+
+    // Gets the literal's text without the type suffix and without underscores.
+    let literal_text = raw_literal_text
+        .chars()
+        .take(raw_literal_text.len() - suffix_len)
+        .filter(|c| *c != '_')
+        .collect::<SmolStr>();
+    let literal_base = IntegerLiteralBase::identify(&literal_text)?;
+
+    for base in IntegerLiteralBase::bases() {
+        if *base == literal_base {
+            continue;
+        }
+
+        let mut converted = literal_base.convert(&literal_text, base);
+
+        let label = if let Some(suffix) = &suffix {
+            format!("Convert {} ({}) to {}", &literal_text, suffix, &converted)
+        } else {
+            format!("Convert {} to {}", &literal_text, &converted)
+        };
+
+        // Appends the type suffix back into the new literal if it exists.
+        if let Some(suffix) = &suffix {
+            converted.push_str(&suffix);
+        }
+
+        acc.add_group(
+            &group_id,
+            AssistId("convert_integer_literal", AssistKind::RefactorInline),
+            label,
+            range,
+            |builder| builder.replace(range, converted),
+        );
+    }
+
+    Some(())
+}
+
+#[derive(Debug, PartialEq, Eq)]
+enum IntegerLiteralBase {
+    Binary,
+    Octal,
+    Decimal,
+    Hexadecimal,
+}
+
+impl IntegerLiteralBase {
+    fn identify(literal_text: &str) -> Option<Self> {
+        // We cannot express a literal in anything other than decimal in under 3 characters, so we return here if possible.
+        if literal_text.len() < 3 && literal_text.chars().all(|c| c.is_digit(10)) {
+            return Some(Self::Decimal);
+        }
+
+        let base = match &literal_text[..2] {
+            "0b" => Self::Binary,
+            "0o" => Self::Octal,
+            "0x" => Self::Hexadecimal,
+            _ => Self::Decimal,
+        };
+
+        // Checks that all characters after the base prefix are all valid digits for that base.
+        if literal_text[base.prefix_len()..].chars().all(|c| c.is_digit(base.base())) {
+            Some(base)
+        } else {
+            None
+        }
+    }
+
+    fn convert(&self, literal_text: &str, to: &IntegerLiteralBase) -> String {
+        let digits = &literal_text[self.prefix_len()..];
+        let value = u128::from_str_radix(digits, self.base()).unwrap();
+
+        match to {
+            Self::Binary => format!("0b{:b}", value),
+            Self::Octal => format!("0o{:o}", value),
+            Self::Decimal => value.to_string(),
+            Self::Hexadecimal => format!("0x{:X}", value),
+        }
+    }
+
+    const fn base(&self) -> u32 {
+        match self {
+            Self::Binary => 2,
+            Self::Octal => 8,
+            Self::Decimal => 10,
+            Self::Hexadecimal => 16,
+        }
+    }
+
+    const fn prefix_len(&self) -> usize {
+        match self {
+            Self::Decimal => 0,
+            _ => 2,
+        }
+    }
+
+    const fn bases() -> &'static [IntegerLiteralBase] {
+        &[
+            IntegerLiteralBase::Binary,
+            IntegerLiteralBase::Octal,
+            IntegerLiteralBase::Decimal,
+            IntegerLiteralBase::Hexadecimal,
+        ]
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use super::*;
+    use crate::tests::{check_assist_by_label, check_assist_target};
+
+    #[test]
+    fn binary_target() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 0b1010<|>;", "0b1010");
+    }
+
+    #[test]
+    fn octal_target() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 0o12<|>;", "0o12");
+    }
+
+    #[test]
+    fn decimal_target() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 10<|>;", "10");
+    }
+
+    #[test]
+    fn hexadecimal_target() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 0xA<|>;", "0xA");
+    }
+
+    #[test]
+    fn binary_target_with_underscores() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 0b10_10<|>;", "0b10_10");
+    }
+
+    #[test]
+    fn octal_target_with_underscores() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 0o1_2<|>;", "0o1_2");
+    }
+
+    #[test]
+    fn decimal_target_with_underscores() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 1_0<|>;", "1_0");
+    }
+
+    #[test]
+    fn hexadecimal_target_with_underscores() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 0x_A<|>;", "0x_A");
+    }
+
+    #[test]
+    fn convert_decimal_integer() {
+        let before = "const _: i32 = 1000<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b1111101000;",
+            "Convert 1000 to 0b1111101000",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o1750;",
+            "Convert 1000 to 0o1750",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0x3E8;",
+            "Convert 1000 to 0x3E8",
+        );
+    }
+
+    // Decimal numbers under 3 digits have a special case where they return early because we can't fit a
+    // other base's prefix, so we have a separate test for that.
+    #[test]
+    fn convert_small_decimal_integer() {
+        let before = "const _: i32 = 10<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b1010;",
+            "Convert 10 to 0b1010",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o12;",
+            "Convert 10 to 0o12",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xA;",
+            "Convert 10 to 0xA",
+        );
+    }
+
+    #[test]
+    fn convert_hexadecimal_integer() {
+        let before = "const _: i32 = 0xFF<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b11111111;",
+            "Convert 0xFF to 0b11111111",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o377;",
+            "Convert 0xFF to 0o377",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255;",
+            "Convert 0xFF to 255",
+        );
+    }
+
+    #[test]
+    fn convert_binary_integer() {
+        let before = "const _: i32 = 0b11111111<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o377;",
+            "Convert 0b11111111 to 0o377",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255;",
+            "Convert 0b11111111 to 255",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xFF;",
+            "Convert 0b11111111 to 0xFF",
+        );
+    }
+
+    #[test]
+    fn convert_octal_integer() {
+        let before = "const _: i32 = 0o377<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b11111111;",
+            "Convert 0o377 to 0b11111111",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255;",
+            "Convert 0o377 to 255",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xFF;",
+            "Convert 0o377 to 0xFF",
+        );
+    }
+
+    #[test]
+    fn convert_decimal_integer_with_underscores() {
+        let before = "const _: i32 = 1_00_0<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b1111101000;",
+            "Convert 1000 to 0b1111101000",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o1750;",
+            "Convert 1000 to 0o1750",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0x3E8;",
+            "Convert 1000 to 0x3E8",
+        );
+    }
+
+    #[test]
+    fn convert_small_decimal_integer_with_underscores() {
+        let before = "const _: i32 = 1_0<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b1010;",
+            "Convert 10 to 0b1010",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o12;",
+            "Convert 10 to 0o12",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xA;",
+            "Convert 10 to 0xA",
+        );
+    }
+
+    #[test]
+    fn convert_hexadecimal_integer_with_underscores() {
+        let before = "const _: i32 = 0x_F_F<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b11111111;",
+            "Convert 0xFF to 0b11111111",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o377;",
+            "Convert 0xFF to 0o377",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255;",
+            "Convert 0xFF to 255",
+        );
+    }
+
+    #[test]
+    fn convert_binary_integer_with_underscores() {
+        let before = "const _: i32 = 0b1111_1111<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o377;",
+            "Convert 0b11111111 to 0o377",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255;",
+            "Convert 0b11111111 to 255",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xFF;",
+            "Convert 0b11111111 to 0xFF",
+        );
+    }
+
+    #[test]
+    fn convert_octal_integer_with_underscores() {
+        let before = "const _: i32 = 0o3_77<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b11111111;",
+            "Convert 0o377 to 0b11111111",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255;",
+            "Convert 0o377 to 255",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xFF;",
+            "Convert 0o377 to 0xFF",
+        );
+    }
+
+    #[test]
+    fn convert_decimal_integer_with_suffix() {
+        let before = "const _: i32 = 1000i32<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b1111101000i32;",
+            "Convert 1000 (i32) to 0b1111101000",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o1750i32;",
+            "Convert 1000 (i32) to 0o1750",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0x3E8i32;",
+            "Convert 1000 (i32) to 0x3E8",
+        );
+    }
+
+    #[test]
+    fn convert_small_decimal_integer_with_suffix() {
+        let before = "const _: i32 = 10i32<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b1010i32;",
+            "Convert 10 (i32) to 0b1010",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o12i32;",
+            "Convert 10 (i32) to 0o12",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xAi32;",
+            "Convert 10 (i32) to 0xA",
+        );
+    }
+
+    #[test]
+    fn convert_hexadecimal_integer_with_suffix() {
+        let before = "const _: i32 = 0xFFi32<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b11111111i32;",
+            "Convert 0xFF (i32) to 0b11111111",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o377i32;",
+            "Convert 0xFF (i32) to 0o377",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255i32;",
+            "Convert 0xFF (i32) to 255",
+        );
+    }
+
+    #[test]
+    fn convert_binary_integer_with_suffix() {
+        let before = "const _: i32 = 0b11111111i32<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o377i32;",
+            "Convert 0b11111111 (i32) to 0o377",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255i32;",
+            "Convert 0b11111111 (i32) to 255",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xFFi32;",
+            "Convert 0b11111111 (i32) to 0xFF",
+        );
+    }
+
+    #[test]
+    fn convert_octal_integer_with_suffix() {
+        let before = "const _: i32 = 0o377i32<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b11111111i32;",
+            "Convert 0o377 (i32) to 0b11111111",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255i32;",
+            "Convert 0o377 (i32) to 255",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xFFi32;",
+            "Convert 0o377 (i32) to 0xFF",
+        );
+    }
+
+    #[test]
+    fn convert_decimal_integer_with_underscores_and_suffix() {
+        let before = "const _: i32 = 1_00_0i32<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b1111101000i32;",
+            "Convert 1000 (i32) to 0b1111101000",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o1750i32;",
+            "Convert 1000 (i32) to 0o1750",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0x3E8i32;",
+            "Convert 1000 (i32) to 0x3E8",
+        );
+    }
+
+    #[test]
+    fn convert_small_decimal_integer_with_underscores_and_suffix() {
+        let before = "const _: i32 = 1_0i32<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b1010i32;",
+            "Convert 10 (i32) to 0b1010",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o12i32;",
+            "Convert 10 (i32) to 0o12",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xAi32;",
+            "Convert 10 (i32) to 0xA",
+        );
+    }
+
+    #[test]
+    fn convert_hexadecimal_integer_with_underscores_and_suffix() {
+        let before = "const _: i32 = 0x_F_Fi32<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b11111111i32;",
+            "Convert 0xFF (i32) to 0b11111111",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o377i32;",
+            "Convert 0xFF (i32) to 0o377",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255i32;",
+            "Convert 0xFF (i32) to 255",
+        );
+    }
+
+    #[test]
+    fn convert_binary_integer_with_underscores_and_suffix() {
+        let before = "const _: i32 = 0b1111_1111i32<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o377i32;",
+            "Convert 0b11111111 (i32) to 0o377",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255i32;",
+            "Convert 0b11111111 (i32) to 255",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xFFi32;",
+            "Convert 0b11111111 (i32) to 0xFF",
+        );
+    }
+
+    #[test]
+    fn convert_octal_integer_with_underscores_and_suffix() {
+        let before = "const _: i32 = 0o3_77i32<|>;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b11111111i32;",
+            "Convert 0o377 (i32) to 0b11111111",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255i32;",
+            "Convert 0o377 (i32) to 255",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xFFi32;",
+            "Convert 0o377 (i32) to 0xFF",
+        );
+    }
+}