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| 1 | +use syntax::{ |
| 2 | + ast::{Expr, GenericArg}, |
| 3 | + ast::{LetStmt, Type::InferType}, |
| 4 | + AstNode, TextRange, |
| 5 | +}; |
| 6 | + |
| 7 | +use crate::{ |
| 8 | + assist_context::{AssistContext, Assists}, |
| 9 | + AssistId, AssistKind, |
| 10 | +}; |
| 11 | + |
| 12 | +// Assist: replace_turbofish_with_explicit_type |
| 13 | +// |
| 14 | +// Converts `::<_>` to an explicit type assignment. |
| 15 | +// |
| 16 | +// ``` |
| 17 | +// fn make<T>() -> T { ) } |
| 18 | +// fn main() { |
| 19 | +// let a = make$0::<i32>(); |
| 20 | +// } |
| 21 | +// ``` |
| 22 | +// -> |
| 23 | +// ``` |
| 24 | +// fn make<T>() -> T { ) } |
| 25 | +// fn main() { |
| 26 | +// let a: i32 = make(); |
| 27 | +// } |
| 28 | +// ``` |
| 29 | +pub(crate) fn replace_turbofish_with_explicit_type( |
| 30 | + acc: &mut Assists, |
| 31 | + ctx: &AssistContext, |
| 32 | +) -> Option<()> { |
| 33 | + let let_stmt = ctx.find_node_at_offset::<LetStmt>()?; |
| 34 | + |
| 35 | + let initializer = let_stmt.initializer()?; |
| 36 | + |
| 37 | + let generic_args = match &initializer { |
| 38 | + Expr::MethodCallExpr(ce) => ce.generic_arg_list()?, |
| 39 | + Expr::CallExpr(ce) => { |
| 40 | + if let Expr::PathExpr(pe) = ce.expr()? { |
| 41 | + pe.path()?.segment()?.generic_arg_list()? |
| 42 | + } else { |
| 43 | + cov_mark::hit!(not_applicable_if_non_path_function_call); |
| 44 | + return None; |
| 45 | + } |
| 46 | + } |
| 47 | + _ => { |
| 48 | + cov_mark::hit!(not_applicable_if_non_function_call_initializer); |
| 49 | + return None; |
| 50 | + } |
| 51 | + }; |
| 52 | + |
| 53 | + // Find range of ::<_> |
| 54 | + let colon2 = generic_args.coloncolon_token()?; |
| 55 | + let r_angle = generic_args.r_angle_token()?; |
| 56 | + let turbofish_range = TextRange::new(colon2.text_range().start(), r_angle.text_range().end()); |
| 57 | + |
| 58 | + let turbofish_args: Vec<GenericArg> = generic_args.generic_args().into_iter().collect(); |
| 59 | + |
| 60 | + // Find type of ::<_> |
| 61 | + if turbofish_args.len() != 1 { |
| 62 | + cov_mark::hit!(not_applicable_if_not_single_arg); |
| 63 | + return None; |
| 64 | + } |
| 65 | + |
| 66 | + // An improvement would be to check that this is correctly part of the return value of the |
| 67 | + // function call, or sub in the actual return type. |
| 68 | + let turbofish_type = &turbofish_args[0]; |
| 69 | + |
| 70 | + let initializer_start = initializer.syntax().text_range().start(); |
| 71 | + if ctx.offset() > turbofish_range.end() || ctx.offset() < initializer_start { |
| 72 | + cov_mark::hit!(not_applicable_outside_turbofish); |
| 73 | + return None; |
| 74 | + } |
| 75 | + |
| 76 | + if let None = let_stmt.colon_token() { |
| 77 | + // If there's no colon in a let statement, then there is no explicit type. |
| 78 | + // let x = fn::<...>(); |
| 79 | + let ident_range = let_stmt.pat()?.syntax().text_range(); |
| 80 | + |
| 81 | + return acc.add( |
| 82 | + AssistId("replace_turbofish_with_explicit_type", AssistKind::RefactorRewrite), |
| 83 | + "Replace turbofish with explicit type", |
| 84 | + TextRange::new(initializer_start, turbofish_range.end()), |
| 85 | + |builder| { |
| 86 | + builder.insert(ident_range.end(), format!(": {}", turbofish_type)); |
| 87 | + builder.delete(turbofish_range); |
| 88 | + }, |
| 89 | + ); |
| 90 | + } else if let Some(InferType(t)) = let_stmt.ty() { |
| 91 | + // If there's a type inferrence underscore, we can offer to replace it with the type in |
| 92 | + // the turbofish. |
| 93 | + // let x: _ = fn::<...>(); |
| 94 | + let underscore_range = t.syntax().text_range(); |
| 95 | + |
| 96 | + return acc.add( |
| 97 | + AssistId("replace_turbofish_with_explicit_type", AssistKind::RefactorRewrite), |
| 98 | + "Replace `_` with turbofish type", |
| 99 | + turbofish_range, |
| 100 | + |builder| { |
| 101 | + builder.replace(underscore_range, turbofish_type.to_string()); |
| 102 | + builder.delete(turbofish_range); |
| 103 | + }, |
| 104 | + ); |
| 105 | + } |
| 106 | + |
| 107 | + None |
| 108 | +} |
| 109 | + |
| 110 | +#[cfg(test)] |
| 111 | +mod tests { |
| 112 | + use super::*; |
| 113 | + |
| 114 | + use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target}; |
| 115 | + |
| 116 | + #[test] |
| 117 | + fn replaces_turbofish_for_vec_string() { |
| 118 | + check_assist( |
| 119 | + replace_turbofish_with_explicit_type, |
| 120 | + r#" |
| 121 | +fn make<T>() -> T {} |
| 122 | +fn main() { |
| 123 | + let a = make$0::<Vec<String>>(); |
| 124 | +} |
| 125 | +"#, |
| 126 | + r#" |
| 127 | +fn make<T>() -> T {} |
| 128 | +fn main() { |
| 129 | + let a: Vec<String> = make(); |
| 130 | +} |
| 131 | +"#, |
| 132 | + ); |
| 133 | + } |
| 134 | + |
| 135 | + #[test] |
| 136 | + fn replaces_method_calls() { |
| 137 | + // foo.make() is a method call which uses a different expr in the let initializer |
| 138 | + check_assist( |
| 139 | + replace_turbofish_with_explicit_type, |
| 140 | + r#" |
| 141 | +fn make<T>() -> T {} |
| 142 | +fn main() { |
| 143 | + let a = foo.make$0::<Vec<String>>(); |
| 144 | +} |
| 145 | +"#, |
| 146 | + r#" |
| 147 | +fn make<T>() -> T {} |
| 148 | +fn main() { |
| 149 | + let a: Vec<String> = foo.make(); |
| 150 | +} |
| 151 | +"#, |
| 152 | + ); |
| 153 | + } |
| 154 | + |
| 155 | + #[test] |
| 156 | + fn replace_turbofish_target() { |
| 157 | + check_assist_target( |
| 158 | + replace_turbofish_with_explicit_type, |
| 159 | + r#" |
| 160 | +fn make<T>() -> T {} |
| 161 | +fn main() { |
| 162 | + let a = $0make::<Vec<String>>(); |
| 163 | +} |
| 164 | +"#, |
| 165 | + r#"make::<Vec<String>>"#, |
| 166 | + ); |
| 167 | + } |
| 168 | + |
| 169 | + #[test] |
| 170 | + fn not_applicable_outside_turbofish() { |
| 171 | + cov_mark::check!(not_applicable_outside_turbofish); |
| 172 | + check_assist_not_applicable( |
| 173 | + replace_turbofish_with_explicit_type, |
| 174 | + r#" |
| 175 | +fn make<T>() -> T {} |
| 176 | +fn main() { |
| 177 | + let $0a = make::<Vec<String>>(); |
| 178 | +} |
| 179 | +"#, |
| 180 | + ); |
| 181 | + } |
| 182 | + |
| 183 | + #[test] |
| 184 | + fn replace_inferred_type_placeholder() { |
| 185 | + check_assist( |
| 186 | + replace_turbofish_with_explicit_type, |
| 187 | + r#" |
| 188 | +fn make<T>() -> T {} |
| 189 | +fn main() { |
| 190 | + let a: _ = make$0::<Vec<String>>(); |
| 191 | +} |
| 192 | +"#, |
| 193 | + r#" |
| 194 | +fn make<T>() -> T {} |
| 195 | +fn main() { |
| 196 | + let a: Vec<String> = make(); |
| 197 | +} |
| 198 | +"#, |
| 199 | + ); |
| 200 | + } |
| 201 | + |
| 202 | + #[test] |
| 203 | + fn not_applicable_constant_initializer() { |
| 204 | + cov_mark::check!(not_applicable_if_non_function_call_initializer); |
| 205 | + check_assist_not_applicable( |
| 206 | + replace_turbofish_with_explicit_type, |
| 207 | + r#" |
| 208 | +fn make<T>() -> T {} |
| 209 | +fn main() { |
| 210 | + let a = "foo"$0; |
| 211 | +} |
| 212 | +"#, |
| 213 | + ); |
| 214 | + } |
| 215 | + |
| 216 | + #[test] |
| 217 | + fn not_applicable_non_path_function_call() { |
| 218 | + cov_mark::check!(not_applicable_if_non_path_function_call); |
| 219 | + check_assist_not_applicable( |
| 220 | + replace_turbofish_with_explicit_type, |
| 221 | + r#" |
| 222 | +fn make<T>() -> T {} |
| 223 | +fn main() { |
| 224 | + $0let a = (|| {})(); |
| 225 | +} |
| 226 | +"#, |
| 227 | + ); |
| 228 | + } |
| 229 | + |
| 230 | + #[test] |
| 231 | + fn non_applicable_multiple_generic_args() { |
| 232 | + cov_mark::check!(not_applicable_if_not_single_arg); |
| 233 | + check_assist_not_applicable( |
| 234 | + replace_turbofish_with_explicit_type, |
| 235 | + r#" |
| 236 | +fn make<T>() -> T {} |
| 237 | +fn main() { |
| 238 | + let a = make$0::<Vec<String>, i32>(); |
| 239 | +} |
| 240 | +"#, |
| 241 | + ); |
| 242 | + } |
| 243 | +} |
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