find_path: Builtins are always in scope

Fixes #3977.

2 files changed, 50 insertions, 25 deletions

diff --git a/crates/ra_hir_def/src/builtin_type.rs b/crates/ra_hir_def/src/builtin_type.rs
index d14901a9b..0f872b5c0 100644
--- a/crates/ra_hir_def/src/builtin_type.rs
+++ b/crates/ra_hir_def/src/builtin_type.rs
@@ -5,7 +5,7 @@
 
 use std::fmt;
 
-use hir_expand::name::{name, Name};
+use hir_expand::name::{name, AsName, Name};
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
 pub enum Signedness {
@@ -75,33 +75,39 @@ impl BuiltinType {
     ];
 }
 
-impl fmt::Display for BuiltinType {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let type_name = match self {
-            BuiltinType::Char => "char",
-            BuiltinType::Bool => "bool",
-            BuiltinType::Str => "str",
+impl AsName for BuiltinType {
+    fn as_name(&self) -> Name {
+        match self {
+            BuiltinType::Char => name![char],
+            BuiltinType::Bool => name![bool],
+            BuiltinType::Str => name![str],
             BuiltinType::Int(BuiltinInt { signedness, bitness }) => match (signedness, bitness) {
-                (Signedness::Signed, IntBitness::Xsize) => "isize",
-                (Signedness::Signed, IntBitness::X8) => "i8",
-                (Signedness::Signed, IntBitness::X16) => "i16",
-                (Signedness::Signed, IntBitness::X32) => "i32",
-                (Signedness::Signed, IntBitness::X64) => "i64",
-                (Signedness::Signed, IntBitness::X128) => "i128",
-
-                (Signedness::Unsigned, IntBitness::Xsize) => "usize",
-                (Signedness::Unsigned, IntBitness::X8) => "u8",
-                (Signedness::Unsigned, IntBitness::X16) => "u16",
-                (Signedness::Unsigned, IntBitness::X32) => "u32",
-                (Signedness::Unsigned, IntBitness::X64) => "u64",
-                (Signedness::Unsigned, IntBitness::X128) => "u128",
+                (Signedness::Signed, IntBitness::Xsize) => name![isize],
+                (Signedness::Signed, IntBitness::X8) => name![i8],
+                (Signedness::Signed, IntBitness::X16) => name![i16],
+                (Signedness::Signed, IntBitness::X32) => name![i32],
+                (Signedness::Signed, IntBitness::X64) => name![i64],
+                (Signedness::Signed, IntBitness::X128) => name![i128],
+
+                (Signedness::Unsigned, IntBitness::Xsize) => name![usize],
+                (Signedness::Unsigned, IntBitness::X8) => name![u8],
+                (Signedness::Unsigned, IntBitness::X16) => name![u16],
+                (Signedness::Unsigned, IntBitness::X32) => name![u32],
+                (Signedness::Unsigned, IntBitness::X64) => name![u64],
+                (Signedness::Unsigned, IntBitness::X128) => name![u128],
             },
             BuiltinType::Float(BuiltinFloat { bitness }) => match bitness {
-                FloatBitness::X32 => "f32",
-                FloatBitness::X64 => "f64",
+                FloatBitness::X32 => name![f32],
+                FloatBitness::X64 => name![f64],
             },
-        };
-        f.write_str(type_name)
+        }
+    }
+}
+
+impl fmt::Display for BuiltinType {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let type_name = self.as_name();
+        type_name.fmt(f)
     }
 }
 
diff --git a/crates/ra_hir_def/src/find_path.rs b/crates/ra_hir_def/src/find_path.rs
index d58ac6ba5..81eff5bfe 100644
--- a/crates/ra_hir_def/src/find_path.rs
+++ b/crates/ra_hir_def/src/find_path.rs
@@ -7,7 +7,7 @@ use crate::{
     visibility::Visibility,
     CrateId, ModuleDefId, ModuleId,
 };
-use hir_expand::name::{known, Name};
+use hir_expand::name::{known, AsName, Name};
 use test_utils::tested_by;
 
 const MAX_PATH_LEN: usize = 15;
@@ -113,6 +113,11 @@ fn find_path_inner(
         }
     }
 
+    // - if the item is a builtin, it's in scope
+    if let ItemInNs::Types(ModuleDefId::BuiltinType(builtin)) = item {
+        return Some(ModPath::from_segments(PathKind::Plain, vec![builtin.as_name()]));
+    }
+
     // Recursive case:
     // - if the item is an enum variant, refer to it via the enum
     if let Some(ModuleDefId::EnumVariantId(variant)) = item.as_module_def_id() {
@@ -523,4 +528,18 @@ mod tests {
         "#;
         check_found_path(code, "megaalloc::Arc");
     }
+
+    #[test]
+    fn builtins_are_in_scope() {
+        let code = r#"
+        //- /main.rs
+        <|>
+
+        pub mod primitive {
+            pub use u8;
+        }
+        "#;
+        check_found_path(code, "u8");
+        check_found_path(code, "u16");
+    }
 }