Fix resolution of local items that shadow imported ones (#5418)

## Description

Closes #5383.

#5383 blocks PR #5306.

## Checklist

- [x] I have linked to any relevant issues.
- [x] I have commented my code, particularly in hard-to-understand
areas.
- [ ] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [x] I have added tests that prove my fix is effective or that my
feature works.
- [ ] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [x] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [x] I have requested a review from the relevant team or maintainers.

sway-core/src/semantic_analysis/namespace/items.rs

@@ -28,6 +28,7 @@ pub(crate) enum GlobImport {
 }
 
 pub(super) type SymbolMap = im::OrdMap<Ident, ty::TyDecl>;
+// The final `bool` field of `UseSynonyms` is true if the `Vec<Ident>` path is absolute.
 pub(super) type UseSynonyms = im::HashMap<Ident, (Vec<Ident>, GlobImport, ty::TyDecl, bool)>;
 pub(super) type UseAliases = im::HashMap<String, Ident>;
 

sway-core/src/semantic_analysis/namespace/root.rs

@@ -342,8 +342,19 @@ impl Root {
         match module.use_synonyms.get(symbol) {
             Some((_, _, decl @ ty::TyDecl::EnumVariantDecl { .. }, _)) => Ok(decl.clone()),
             Some((src_path, _, _, _)) if mod_path != src_path => {
-                // TODO: check that the symbol import is public?
-                self.resolve_symbol(handler, engines, src_path, true_symbol, self_type)
+                // If the symbol is imported, before resolving to it,
+                // we need to check if there is a local symbol withing the module with
+                // the same name, and if yes resolve to the local symbol, because it
+                // shadows the import.
+                // Note that we can have two situations here:
+                // - glob-import, in which case the local symbol simply shadows the glob-imported one.
+                // - non-glob import, in which case we will already have a name clash reported
+                //   as an error, but still have to resolve to the local module symbol
+                //   if it exists.
+                match module.symbols.get(true_symbol) {
+                    Some(decl) => Ok(decl.clone()),
+                    None => self.resolve_symbol(handler, engines, src_path, true_symbol, self_type),
+                }
             }
             _ => module
                 .check_symbol(true_symbol)

sway-core/src/semantic_analysis/type_check_context.rs

@@ -606,7 +606,7 @@ impl<'a> TypeCheckContext<'a> {
     ///
     /// The `mod_path` is significant here as we assume the resolution is done within the
     /// context of the module pointed to by `mod_path` and will only check the call path prefixes
-    /// and the symbol's own visibility
+    /// and the symbol's own visibility.
     pub(crate) fn resolve_call_path_with_visibility_check_and_modpath(
         &self,
         handler: &Handler,

test/src/e2e_vm_tests/test_programs/should_fail/resolve_local_items_that_shadow_imports/Forc.lock

@@ -0,0 +1,13 @@
+[[package]]
+name = "core"
+source = "path+from-root-8AA4CB15A1A05A28"
+
+[[package]]
+name = "resolve_local_items_that_shadow_imports"
+source = "member"
+dependencies = ["std"]
+
+[[package]]
+name = "std"
+source = "path+from-root-8AA4CB15A1A05A28"
+dependencies = ["core"]

test/src/e2e_vm_tests/test_programs/should_fail/resolve_local_items_that_shadow_imports/Forc.toml

@@ -0,0 +1,8 @@
+[project]
+name = "resolve_local_items_that_shadow_imports"
+authors = ["Fuel Labs <contact@fuel.sh>"]
+entry = "main.sw"
+license = "Apache-2.0"
+
+[dependencies]
+std = { path = "../../../../../../sway-lib-std" }

test/src/e2e_vm_tests/test_programs/should_fail/resolve_local_items_that_shadow_imports/json_abi_oracle.json

@@ -0,0 +1,25 @@
+{
+  "configurables": [],
+  "functions": [
+    {
+      "attributes": null,
+      "inputs": [],
+      "name": "main",
+      "output": {
+        "name": "",
+        "type": 0,
+        "typeArguments": null
+      }
+    }
+  ],
+  "loggedTypes": [],
+  "messagesTypes": [],
+  "types": [
+    {
+      "components": [],
+      "type": "()",
+      "typeId": 0,
+      "typeParameters": null
+    }
+  ]
+}

test/src/e2e_vm_tests/test_programs/should_fail/resolve_local_items_that_shadow_imports/src/lib.sw

@@ -0,0 +1,19 @@
+library;
+
+pub enum Enum {
+    A: (),
+}
+
+pub struct Struct {
+    x: u64,
+}
+
+pub struct PubStruct {
+   x: u64,
+}
+
+pub struct GenericStruct<T> {
+    x: T,
+}
+
+pub const X: u64 = 0u64;

test/src/e2e_vm_tests/test_programs/should_fail/resolve_local_items_that_shadow_imports/src/main.sw

@@ -0,0 +1,72 @@
+// This test proves that https://github.com/FuelLabs/sway/issues/5383 is fixed.
+
+script;
+
+mod lib;
+
+use lib::Enum;
+use lib::Struct;
+use lib::PubStruct;
+use lib::GenericStruct;
+
+enum Enum {
+    A: (),
+    B: (),
+}
+
+struct Struct {
+   x: u64,
+   y: u64,
+}
+
+impl Struct {
+    fn use_me(self) {
+        poke(self.x);
+        poke(self.y);
+    }
+}
+
+pub struct PubStruct {
+   x: u64,
+   y: u64,
+}
+
+impl PubStruct {
+    fn use_me(self) {
+        poke(self.x);
+        poke(self.y);
+    }
+}
+
+struct GenericStruct<T> {
+    x: T,
+    y: u64,
+}
+
+impl<T> GenericStruct<T> {
+    fn use_me(self) {
+        poke(self.x);
+        poke(self.y);
+    }
+}
+
+pub const X: bool = true;
+
+fn main() {
+    // We must get errors for defining items multiple times,
+    // but that should be all errors.
+    // We shouldn't have any errors below, because the
+    // below items will resolve to local ones.
+    let _ = Struct { x: 0, y: 0 };
+    let _ = PubStruct { x: 0, y: 0 };
+    let _ = GenericStruct { x: 0, y: 0 };
+    let _ = Enum::B;
+    let _: bool = X;
+
+    Struct { x: 0, y: 0 }.use_me();
+    PubStruct { x: 0, y: 0 }.use_me();
+    GenericStruct { x: 0, y: 0 }.use_me();
+    poke(Enum::A);
+}
+
+fn poke<T>(_x: T) { }

test/src/e2e_vm_tests/test_programs/should_fail/resolve_local_items_that_shadow_imports/test.toml

@@ -0,0 +1,19 @@
+category = "fail"
+
+#check: $()error
+#check: $()enum Enum {
+#nextln: $()Name "Enum" is defined multiple times.
+
+#check: $()error
+#check: $()struct Struct {
+#nextln: $()Name "Struct" is defined multiple times.
+
+#check: $()error
+#check: $()pub struct PubStruct {
+#nextln: $()Name "PubStruct" is defined multiple times.
+
+#check: $()error
+#check: $()struct GenericStruct<T> {
+#nextln: $()Name "GenericStruct" is defined multiple times.
+
+#not: $()error

test/src/e2e_vm_tests/test_programs/should_pass/language/diverging_exprs/src/main.sw

@@ -1,10 +1,5 @@
 script;
 
-fn revert<T>() -> T {
-    let code = 1u64;
-    __revert(code)
-}
-
 fn diverge_in_let_body() -> u64 {
     let _x: bool =  {
         return 5;

test/src/e2e_vm_tests/test_programs/should_pass/language/generic_type_inference/json_abi_oracle.json

@@ -12,37 +12,14 @@
       }
     }
   ],
-  "loggedTypes": [
-    {
-      "logId": 0,
-      "loggedType": {
-        "name": "",
-        "type": 1,
-        "typeArguments": null
-      }
-    },
-    {
-      "logId": 1,
-      "loggedType": {
-        "name": "",
-        "type": 1,
-        "typeArguments": null
-      }
-    }
-  ],
+  "loggedTypes": [],
   "messagesTypes": [],
   "types": [
     {
       "components": [],
       "type": "()",
       "typeId": 0,
       "typeParameters": null
-    },
-    {
-      "components": null,
-      "type": "u64",
-      "typeId": 1,
-      "typeParameters": null
     }
   ]
 }

test/src/e2e_vm_tests/test_programs/should_pass/language/generic_type_inference/src/main.sw

@@ -8,6 +8,12 @@ struct CustomType {
     name: str,
 }
 
+impl CustomType {
+    fn use_me(self) {
+        poke(self.name);
+    }
+}
+
 enum MyResult<T, E> {
     Ok: T,
     Err: E,
@@ -56,12 +62,15 @@ fn test_try_from() {
 }
 
 fn main() {
-    sell_product();
+    let _ = sell_product();
     simple_vec_test();
     complex_vec_test();
     simple_option_generics_test();
     test_assert_eq_u64();
     test_try_from();
+
+    // Suppress DCA warnings.
+    CustomType { name: "" }.use_me();
 }
 
 fn sell_product() -> MyResult<bool, CustomType> {
@@ -73,3 +82,5 @@ fn sell_product() -> MyResult<bool, CustomType> {
 
     return MyResult::Ok(false);
 }
+
+fn poke<T>(_x: T) { }

test/src/e2e_vm_tests/test_programs/should_pass/resolve_local_items_that_shadow_imports/Forc.lock

@@ -0,0 +1,13 @@
+[[package]]
+name = "core"
+source = "path+from-root-8AA4CB15A1A05A28"
+
+[[package]]
+name = "resolve_local_items_that_shadow_imports"
+source = "member"
+dependencies = ["std"]
+
+[[package]]
+name = "std"
+source = "path+from-root-8AA4CB15A1A05A28"
+dependencies = ["core"]

test/src/e2e_vm_tests/test_programs/should_pass/resolve_local_items_that_shadow_imports/Forc.toml

@@ -0,0 +1,8 @@
+[project]
+name = "resolve_local_items_that_shadow_imports"
+authors = ["Fuel Labs <contact@fuel.sh>"]
+entry = "main.sw"
+license = "Apache-2.0"
+
+[dependencies]
+std = { path = "../../../../../../sway-lib-std" }

test/src/e2e_vm_tests/test_programs/should_pass/resolve_local_items_that_shadow_imports/json_abi_oracle.json

@@ -0,0 +1,25 @@
+{
+  "configurables": [],
+  "functions": [
+    {
+      "attributes": null,
+      "inputs": [],
+      "name": "main",
+      "output": {
+        "name": "",
+        "type": 0,
+        "typeArguments": null
+      }
+    }
+  ],
+  "loggedTypes": [],
+  "messagesTypes": [],
+  "types": [
+    {
+      "components": [],
+      "type": "()",
+      "typeId": 0,
+      "typeParameters": null
+    }
+  ]
+}

test/src/e2e_vm_tests/test_programs/should_pass/resolve_local_items_that_shadow_imports/src/lib.sw

@@ -0,0 +1,19 @@
+library;
+
+pub enum Enum {
+    A: (),
+}
+
+pub struct Struct {
+    x: u64,
+}
+
+pub struct PubStruct {
+   x: u64,
+}
+
+pub struct GenericStruct<T> {
+    x: T,
+}
+
+pub const X: u64 = 0u64;