TY: Improve indexing of primitive types

impl blocks for primitive types are not correctly indexed.
This causes problems with autocompletion and method resolving
around primitive types.

In Rust primitive types are only allowed a single
impl block that must be annotated with the "lang" attribute.
The primitive types bool does not have an inherent impl.

See rust-lang/rust#23104
and the error code E0390 for more details.

Our implementation does not enforce this limitation
and also accept user defined impl blocks.

Author: kumbayo

src/main/kotlin/org/rust/lang/core/stubs/StubImplementations.kt

@@ -24,7 +24,7 @@ class RsFileStub : PsiFileStubImpl<RsFile> {
 
     object Type : IStubFileElementType<RsFileStub>(RsLanguage) {
         // Bump this number if Stub structure changes
-        override fun getStubVersion(): Int = 69
+        override fun getStubVersion(): Int = 70
 
         override fun getBuilder(): StubBuilder = object : DefaultStubBuilder() {
             override fun createStubForFile(file: PsiFile): StubElement<*> = RsFileStub(file as RsFile)

src/main/kotlin/org/rust/lang/core/types/TyFingerprint.kt

@@ -29,8 +29,8 @@ data class TyFingerprint constructor(
             is TyStruct -> type.item.name?.let(::TyFingerprint)
             is TyEnum -> type.item.name?.let(::TyFingerprint)
             is TySlice -> TyFingerprint("[T]")
-            is TyStr -> TyFingerprint("str")
             is TyReference -> create(type.referenced)
+            is TyPrimitive -> TyFingerprint(type.toString())
             else -> null
         }
     }

src/main/kotlin/org/rust/lang/core/types/ty/Ty.kt

@@ -82,7 +82,7 @@ fun findImplsAndTraits(project: Project, ty: Ty): Pair<Collection<BoundElement<R
 
     //  XXX: TyStr is TyPrimitive, but we want to handle it separately
         is TyStr -> RsImplIndex.findImpls(project, ty).map { impl -> BoundElement(impl) } to noTraits
-        is TyPrimitive, is TyUnit, is TyUnknown -> noImpls to noTraits
+        is TyUnit, is TyUnknown -> noImpls to noTraits
 
         else -> RsImplIndex.findImpls(project, ty).map { impl ->
             BoundElement(impl, impl.remapTypeParameters(ty.typeParameterValues).orEmpty())

src/test/kotlin/org/rust/lang/core/resolve/RsStdlibResolveTest.kt

@@ -129,6 +129,70 @@ class RsStdlibResolveTest : RsResolveTestBase() {
         }
     """)
 
+    fun `test inherent impl char 1`() = stubOnlyResolve("""
+    //- main.rs
+        fn main() { 'Z'.is_lowercase(); }
+                      //^ ...libstd_unicode/char.rs
+    """)
+
+    fun `test inherent impl char 2`() = expect<IllegalStateException> {
+        stubOnlyResolve("""
+    //- main.rs
+        fn main() { char::is_lowercase('Z'); }
+                        //^ ...libstd_unicode/char.rs
+    """)
+    }
+
+    fun `test inherent impl str 1`() = stubOnlyResolve("""
+    //- main.rs
+        fn main() { "Z".to_uppercase(); }
+                      //^ ...libcollections/str.rs
+    """)
+
+    fun `test inherent impl str 2`() = expect<IllegalStateException> {
+        stubOnlyResolve("""
+    //- main.rs
+        fn main() { str::to_uppercase("Z"); }
+                       //^ ...libcollections/str.rs
+    """)
+    }
+
+    fun `test inherent impl f32 1`() = stubOnlyResolve("""
+    //- main.rs
+        fn main() { 0.0f32.sqrt(); }
+                         //^ ...libstd/f32.rs
+    """)
+
+    fun `test inherent impl f32 2`() = expect<IllegalStateException> {
+        stubOnlyResolve("""
+    //- main.rs
+        fn main() { f32::sqrt(0.0f32); }
+                       //^ ...libstd/f32.rs
+    """)
+    }
+
+    fun `test inherent impl f32 3`() = expect<IllegalStateException> {
+        stubOnlyResolve("""
+    //- main.rs
+        fn main() { <f32>::sqrt(0.0f32); }
+                         //^ ...libstd/f32.rs
+    """)
+    }
+
+    fun `test inherent impl f64 1`() = stubOnlyResolve("""
+    //- main.rs
+        fn main() { 0.0f64.sqrt(); }
+                         //^ ...libstd/f64.rs
+    """)
+
+    fun `test inherent impl f64 2`() = expect<IllegalStateException> {
+        stubOnlyResolve("""
+    //- main.rs
+        fn main() { f64::sqrt(0.0f64); }
+                       //^ ...libstd/f64.rs
+    """)
+    }
+
     fun `test println macro`() = stubOnlyResolve("""
     //- main.rs
         fn main() {