bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/ide-db/src/active_parameter.rs')
-rw-r--r--crates/ide-db/src/active_parameter.rs78
1 files changed, 78 insertions, 0 deletions
diff --git a/crates/ide-db/src/active_parameter.rs b/crates/ide-db/src/active_parameter.rs
new file mode 100644
index 0000000000..788a5ed17e
--- /dev/null
+++ b/crates/ide-db/src/active_parameter.rs
@@ -0,0 +1,78 @@
+//! This module provides functionality for querying callable information about a token.
+
+use either::Either;
+use hir::{Semantics, Type};
+use syntax::{
+ ast::{self, HasArgList, HasName},
+ AstNode, SyntaxToken,
+};
+
+use crate::RootDatabase;
+
+#[derive(Debug)]
+pub struct ActiveParameter {
+ pub ty: Type,
+ pub pat: Either<ast::SelfParam, ast::Pat>,
+}
+
+impl ActiveParameter {
+ /// Returns information about the call argument this token is part of.
+ pub fn at_token(sema: &Semantics<RootDatabase>, token: SyntaxToken) -> Option<Self> {
+ let (signature, active_parameter) = callable_for_token(sema, token)?;
+
+ let idx = active_parameter?;
+ let mut params = signature.params(sema.db);
+ if !(idx < params.len()) {
+ cov_mark::hit!(too_many_arguments);
+ return None;
+ }
+ let (pat, ty) = params.swap_remove(idx);
+ pat.map(|pat| ActiveParameter { ty, pat })
+ }
+
+ pub fn ident(&self) -> Option<ast::Name> {
+ self.pat.as_ref().right().and_then(|param| match param {
+ ast::Pat::IdentPat(ident) => ident.name(),
+ _ => None,
+ })
+ }
+}
+
+/// Returns a [`hir::Callable`] this token is a part of and its argument index of said callable.
+pub fn callable_for_token(
+ sema: &Semantics<RootDatabase>,
+ token: SyntaxToken,
+) -> Option<(hir::Callable, Option<usize>)> {
+ // Find the calling expression and its NameRef
+ let parent = token.parent()?;
+ let calling_node = parent.ancestors().filter_map(ast::CallableExpr::cast).find(|it| {
+ it.arg_list()
+ .map_or(false, |it| it.syntax().text_range().contains(token.text_range().start()))
+ })?;
+
+ callable_for_node(sema, &calling_node, &token)
+}
+
+pub fn callable_for_node(
+ sema: &Semantics<RootDatabase>,
+ calling_node: &ast::CallableExpr,
+ token: &SyntaxToken,
+) -> Option<(hir::Callable, Option<usize>)> {
+ let callable = match &calling_node {
+ ast::CallableExpr::Call(call) => {
+ let expr = call.expr()?;
+ sema.type_of_expr(&expr)?.adjusted().as_callable(sema.db)
+ }
+ ast::CallableExpr::MethodCall(call) => sema.resolve_method_call_as_callable(call),
+ }?;
+ let active_param = if let Some(arg_list) = calling_node.arg_list() {
+ let param = arg_list
+ .args()
+ .take_while(|arg| arg.syntax().text_range().end() <= token.text_range().start())
+ .count();
+ Some(param)
+ } else {
+ None
+ };
+ Some((callable, active_param))
+}