71 lines
2.3 KiB
Rust
71 lines
2.3 KiB
Rust
//! This module provides functionality for querying callable information about a token.
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use either::Either;
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use hir::{Semantics, Type};
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use syntax::{
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ast::{self, HasArgList, HasName},
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AstNode, SyntaxToken,
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};
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use crate::RootDatabase;
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#[derive(Debug)]
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pub struct ActiveParameter {
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pub ty: Type,
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pub pat: Either<ast::SelfParam, ast::Pat>,
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}
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impl ActiveParameter {
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/// Returns information about the call argument this token is part of.
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pub fn at_token(sema: &Semantics<RootDatabase>, token: SyntaxToken) -> Option<Self> {
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let (signature, active_parameter) = callable_for_token(sema, token)?;
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let idx = active_parameter?;
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let mut params = signature.params(sema.db);
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if !(idx < params.len()) {
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cov_mark::hit!(too_many_arguments);
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return None;
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}
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let (pat, ty) = params.swap_remove(idx);
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pat.map(|pat| ActiveParameter { ty, pat })
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}
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pub fn ident(&self) -> Option<ast::Name> {
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self.pat.as_ref().right().and_then(|param| match param {
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ast::Pat::IdentPat(ident) => ident.name(),
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_ => None,
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})
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}
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}
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/// Returns a [`hir::Callable`] this token is a part of and its argument index of said callable.
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pub fn callable_for_token(
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sema: &Semantics<RootDatabase>,
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token: SyntaxToken,
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) -> Option<(hir::Callable, Option<usize>)> {
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// Find the calling expression and it's NameRef
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let parent = token.parent()?;
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let calling_node = parent.ancestors().filter_map(ast::CallableExpr::cast).find(|it| {
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it.arg_list()
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.map_or(false, |it| it.syntax().text_range().contains(token.text_range().start()))
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})?;
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let callable = match &calling_node {
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ast::CallableExpr::Call(call) => {
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let expr = call.expr()?;
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sema.type_of_expr(&expr)?.adjusted().as_callable(sema.db)
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}
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ast::CallableExpr::MethodCall(call) => sema.resolve_method_call_as_callable(call),
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}?;
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let active_param = if let Some(arg_list) = calling_node.arg_list() {
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let param = arg_list
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.args()
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.take_while(|arg| arg.syntax().text_range().end() <= token.text_range().start())
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.count();
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Some(param)
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} else {
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None
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};
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Some((callable, active_param))
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}
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