Split parts of ide_db::call_info off into ide

crates/ide/src/lib.rs

@@ -24,6 +24,7 @@ mod navigation_target;
 
 mod annotations;
 mod call_hierarchy;
+mod call_info;
 mod doc_links;
 mod highlight_related;
 mod expand_macro;
@@ -73,6 +74,7 @@ use crate::navigation_target::{ToNav, TryToNav};
 pub use crate::{
     annotations::{Annotation, AnnotationConfig, AnnotationKind},
     call_hierarchy::CallItem,
+    call_info::CallInfo,
     expand_macro::ExpandedMacro,
     file_structure::{StructureNode, StructureNodeKind},
     folding_ranges::{Fold, FoldKind},
@@ -106,7 +108,6 @@ pub use ide_db::{
         Cancelled, Change, CrateGraph, CrateId, Edition, FileId, FilePosition, FileRange,
         SourceRoot, SourceRootId,
     },
-    call_info::CallInfo,
     label::Label,
     line_index::{LineCol, LineColUtf16, LineIndex},
     search::{ReferenceCategory, SearchScope},
@@ -434,7 +435,7 @@ impl Analysis {
 
     /// Computes parameter information for the given call expression.
     pub fn call_info(&self, position: FilePosition) -> Cancellable<Option<CallInfo>> {
-        self.with_db(|db| ide_db::call_info::call_info(db, position))
+        self.with_db(|db| call_info::call_info(db, position))
     }
 
     /// Computes call hierarchy candidates for the given file position.

crates/ide/src/static_index.rs

@@ -3,18 +3,18 @@
 
 use std::collections::HashMap;
 
-use hir::Semantics;
-use hir::{db::HirDatabase, Crate, Module};
-use ide_db::base_db::{FileId, FileRange, SourceDatabaseExt};
-use ide_db::defs::Definition;
-use ide_db::RootDatabase;
+use hir::{db::HirDatabase, Crate, Module, Semantics};
+use ide_db::{
+    base_db::{FileId, FileRange, SourceDatabaseExt},
+    defs::Definition,
+    RootDatabase,
+};
 use rustc_hash::FxHashSet;
-use syntax::{AstNode, SyntaxKind::*, T};
-use syntax::{SyntaxToken, TextRange};
+use syntax::{AstNode, SyntaxKind::*, SyntaxToken, TextRange, T};
 
-use crate::hover::hover_for_definition;
 use crate::{
-    Analysis, Fold, HoverConfig, HoverDocFormat, HoverResult, InlayHint, InlayHintsConfig, TryToNav,
+    hover::hover_for_definition, Analysis, Fold, HoverConfig, HoverDocFormat, HoverResult,
+    InlayHint, InlayHintsConfig, TryToNav,
 };
 
 /// A static representation of fully analyzed source code.

crates/ide/src/syntax_highlighting/inject.rs

@@ -5,7 +5,8 @@ use std::mem;
 use either::Either;
 use hir::{InFile, Semantics};
 use ide_db::{
-    call_info::ActiveParameter, defs::Definition, helpers::rust_doc::is_rust_fence, SymbolKind,
+    active_parameter::ActiveParameter, defs::Definition, helpers::rust_doc::is_rust_fence,
+    SymbolKind,
 };
 use syntax::{
     ast::{self, AstNode, IsString},

crates/ide_completion/src/context.rs

@@ -3,8 +3,8 @@
 use base_db::SourceDatabaseExt;
 use hir::{Local, Name, ScopeDef, Semantics, SemanticsScope, Type, TypeInfo};
 use ide_db::{
+    active_parameter::ActiveParameter,
     base_db::{FilePosition, SourceDatabase},
-    call_info::ActiveParameter,
     RootDatabase,
 };
 use syntax::{

crates/ide_db/src/active_parameter.rs

@@ -0,0 +1,70 @@
+//! 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 it's 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()))
+    })?;
+
+    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))
+}