Auto merge of #16060 - Veykril:format-args-orphans, r=Veykril

fix: Fix completion failing in `format_args!` with invalid template

6 files changed, 187 insertions, 8 deletions

diff --git a/crates/hir-def/src/body/lower.rs b/crates/hir-def/src/body/lower.rs
index c22bd6e2e57..c6a90932015 100644
--- a/crates/hir-def/src/body/lower.rs
+++ b/crates/hir-def/src/body/lower.rs
@@ -1611,7 +1611,11 @@ impl ExprCollector<'_> {
                     }
                 },
             ),
-            None => FormatArgs { template: Default::default(), arguments: args.finish() },
+            None => FormatArgs {
+                template: Default::default(),
+                arguments: args.finish(),
+                orphans: Default::default(),
+            },
         };
 
         // Create a list of all _unique_ (argument, format trait) combinations.
@@ -1750,7 +1754,13 @@ impl ExprCollector<'_> {
         });
         let unsafe_arg_new = self.alloc_expr_desugared(Expr::Unsafe {
             id: None,
-            statements: Box::default(),
+            // We collect the unused expressions here so that we still infer them instead of
+            // dropping them out of the expression tree
+            statements: fmt
+                .orphans
+                .into_iter()
+                .map(|expr| Statement::Expr { expr, has_semi: true })
+                .collect(),
             tail: Some(unsafe_arg_new),
         });
 
diff --git a/crates/hir-def/src/hir/format_args.rs b/crates/hir-def/src/hir/format_args.rs
index 068abb27a25..7fc33abc7c9 100644
--- a/crates/hir-def/src/hir/format_args.rs
+++ b/crates/hir-def/src/hir/format_args.rs
@@ -3,6 +3,7 @@ use std::mem;
 
 use hir_expand::name::Name;
 use rustc_dependencies::parse_format as parse;
+use stdx::TupleExt;
 use syntax::{
     ast::{self, IsString},
     SmolStr, TextRange, TextSize,
@@ -14,6 +15,7 @@ use crate::hir::ExprId;
 pub struct FormatArgs {
     pub template: Box<[FormatArgsPiece]>,
     pub arguments: FormatArguments,
+    pub orphans: Vec<ExprId>,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -196,7 +198,11 @@ pub(crate) fn parse(
     let is_source_literal = parser.is_source_literal;
     if !parser.errors.is_empty() {
         // FIXME: Diagnose
-        return FormatArgs { template: Default::default(), arguments: args.finish() };
+        return FormatArgs {
+            template: Default::default(),
+            arguments: args.finish(),
+            orphans: vec![],
+        };
     }
 
     let to_span = |inner_span: parse::InnerSpan| {
@@ -419,7 +425,11 @@ pub(crate) fn parse(
         // FIXME: Diagnose
     }
 
-    FormatArgs { template: template.into_boxed_slice(), arguments: args.finish() }
+    FormatArgs {
+        template: template.into_boxed_slice(),
+        arguments: args.finish(),
+        orphans: unused.into_iter().map(TupleExt::head).collect(),
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
diff --git a/crates/ide-completion/src/tests/expression.rs b/crates/ide-completion/src/tests/expression.rs
index e6969c8db30..b4f936b35ae 100644
--- a/crates/ide-completion/src/tests/expression.rs
+++ b/crates/ide-completion/src/tests/expression.rs
@@ -1094,3 +1094,157 @@ pub struct UnstableButWeAreOnNightlyAnyway;
         "#]],
     );
 }
+
+#[test]
+fn inside_format_args_completions_work() {
+    check_empty(
+        r#"
+//- minicore: fmt
+struct Foo;
+impl Foo {
+    fn foo(&self) {}
+}
+
+fn main() {
+    format_args!("{}", Foo.$0);
+}
+"#,
+        expect![[r#"
+            me foo()  fn(&self)
+            sn box    Box::new(expr)
+            sn call   function(expr)
+            sn dbg    dbg!(expr)
+            sn dbgr   dbg!(&expr)
+            sn match  match expr {}
+            sn ref    &expr
+            sn refm   &mut expr
+            sn unsafe unsafe {}
+        "#]],
+    );
+    check_empty(
+        r#"
+//- minicore: fmt
+struct Foo;
+impl Foo {
+    fn foo(&self) {}
+}
+
+fn main() {
+    format_args!("{}", Foo.f$0);
+}
+"#,
+        expect![[r#"
+            me foo()  fn(&self)
+            sn box    Box::new(expr)
+            sn call   function(expr)
+            sn dbg    dbg!(expr)
+            sn dbgr   dbg!(&expr)
+            sn match  match expr {}
+            sn ref    &expr
+            sn refm   &mut expr
+            sn unsafe unsafe {}
+        "#]],
+    );
+}
+
+#[test]
+fn inside_faulty_format_args_completions_work() {
+    check_empty(
+        r#"
+//- minicore: fmt
+struct Foo;
+impl Foo {
+    fn foo(&self) {}
+}
+
+fn main() {
+    format_args!("", Foo.$0);
+}
+"#,
+        expect![[r#"
+            me foo()  fn(&self)
+            sn box    Box::new(expr)
+            sn call   function(expr)
+            sn dbg    dbg!(expr)
+            sn dbgr   dbg!(&expr)
+            sn match  match expr {}
+            sn ref    &expr
+            sn refm   &mut expr
+            sn unsafe unsafe {}
+        "#]],
+    );
+    check_empty(
+        r#"
+//- minicore: fmt
+struct Foo;
+impl Foo {
+    fn foo(&self) {}
+}
+
+fn main() {
+    format_args!("", Foo.f$0);
+}
+"#,
+        expect![[r#"
+            me foo()  fn(&self)
+            sn box    Box::new(expr)
+            sn call   function(expr)
+            sn dbg    dbg!(expr)
+            sn dbgr   dbg!(&expr)
+            sn match  match expr {}
+            sn ref    &expr
+            sn refm   &mut expr
+            sn unsafe unsafe {}
+        "#]],
+    );
+    check_empty(
+        r#"
+//- minicore: fmt
+struct Foo;
+impl Foo {
+    fn foo(&self) {}
+}
+
+fn main() {
+    format_args!("{} {named} {captured} {named} {}", a, named = c, Foo.f$0);
+}
+"#,
+        expect![[r#"
+            me foo()  fn(&self)
+            sn box    Box::new(expr)
+            sn call   function(expr)
+            sn dbg    dbg!(expr)
+            sn dbgr   dbg!(&expr)
+            sn match  match expr {}
+            sn ref    &expr
+            sn refm   &mut expr
+            sn unsafe unsafe {}
+        "#]],
+    );
+    check_empty(
+        r#"
+//- minicore: fmt
+struct Foo;
+impl Foo {
+    fn foo(&self) {}
+}
+
+fn main() {
+    format_args!("{", Foo.f$0);
+}
+"#,
+        expect![[r#"
+            sn box    Box::new(expr)
+            sn call   function(expr)
+            sn dbg    dbg!(expr)
+            sn dbgr   dbg!(&expr)
+            sn if     if expr {}
+            sn match  match expr {}
+            sn not    !expr
+            sn ref    &expr
+            sn refm   &mut expr
+            sn unsafe unsafe {}
+            sn while  while expr {}
+        "#]],
+    );
+}
diff --git a/crates/ide/src/view_hir.rs b/crates/ide/src/view_hir.rs
index d2bbbf6d26a..738b370a068 100644
--- a/crates/ide/src/view_hir.rs
+++ b/crates/ide/src/view_hir.rs
@@ -1,7 +1,7 @@
 use hir::{DefWithBody, Semantics};
 use ide_db::base_db::FilePosition;
 use ide_db::RootDatabase;
-use syntax::{algo::find_node_at_offset, ast, AstNode};
+use syntax::{algo::ancestors_at_offset, ast, AstNode};
 
 // Feature: View Hir
 //
@@ -19,7 +19,9 @@ fn body_hir(db: &RootDatabase, position: FilePosition) -> Option<String> {
     let sema = Semantics::new(db);
     let source_file = sema.parse(position.file_id);
 
-    let item = find_node_at_offset::<ast::Item>(source_file.syntax(), position.offset)?;
+    let item = ancestors_at_offset(source_file.syntax(), position.offset)
+        .filter(|it| ast::MacroCall::can_cast(it.kind()))
+        .find_map(ast::Item::cast)?;
     let def: DefWithBody = match item {
         ast::Item::Fn(it) => sema.to_def(&it)?.into(),
         ast::Item::Const(it) => sema.to_def(&it)?.into(),
diff --git a/crates/ide/src/view_mir.rs b/crates/ide/src/view_mir.rs
index a36aba58bc0..52ed420669a 100644
--- a/crates/ide/src/view_mir.rs
+++ b/crates/ide/src/view_mir.rs
@@ -1,7 +1,7 @@
 use hir::{DefWithBody, Semantics};
 use ide_db::base_db::FilePosition;
 use ide_db::RootDatabase;
-use syntax::{algo::find_node_at_offset, ast, AstNode};
+use syntax::{algo::ancestors_at_offset, ast, AstNode};
 
 // Feature: View Mir
 //
@@ -18,7 +18,9 @@ fn body_mir(db: &RootDatabase, position: FilePosition) -> Option<String> {
     let sema = Semantics::new(db);
     let source_file = sema.parse(position.file_id);
 
-    let item = find_node_at_offset::<ast::Item>(source_file.syntax(), position.offset)?;
+    let item = ancestors_at_offset(source_file.syntax(), position.offset)
+        .filter(|it| ast::MacroCall::can_cast(it.kind()))
+        .find_map(ast::Item::cast)?;
     let def: DefWithBody = match item {
         ast::Item::Fn(it) => sema.to_def(&it)?.into(),
         ast::Item::Const(it) => sema.to_def(&it)?.into(),
diff --git a/crates/rust-analyzer/tests/slow-tests/tidy.rs b/crates/rust-analyzer/tests/slow-tests/tidy.rs
index 45adbf5c573..dba336ea7d6 100644
--- a/crates/rust-analyzer/tests/slow-tests/tidy.rs
+++ b/crates/rust-analyzer/tests/slow-tests/tidy.rs
@@ -250,6 +250,7 @@ fn check_dbg(path: &Path, text: &str) {
         // We have .dbg postfix
         "ide-completion/src/completions/postfix.rs",
         "ide-completion/src/completions/keyword.rs",
+        "ide-completion/src/tests/expression.rs",
         "ide-completion/src/tests/proc_macros.rs",
         // The documentation in string literals may contain anything for its own purposes
         "ide-completion/src/lib.rs",