Implement ADR-0078: single-candidate import resolution

crates/rue-air/src/sema/provider.rs

@@ -181,8 +181,6 @@ pub enum ImportResolution {
     /// Exactly one directive names it, but the specifier is malformed (it
     /// normalizes to an empty module path).
     Rejected,
-    /// Multiple directives in the consulting module name the same target.
-    Ambiguous,
 }
 
 /// Whether a receiver member is an instance method (takes a `self` receiver) or

crates/rue-cli-tests/cases/array_element_module.toml

@@ -22,7 +22,7 @@ compile_fail = true
 error_contains = ["E0206", "<module>"]
 files = [
     { path = "main.rue", source = """
-fn main() -> i32 { let h = @import("helper"); let arr = [h, h]; 0 }
+fn main() -> i32 { let h = @import("helper.rue"); let arr = [h, h]; 0 }
 """ },
     { path = "helper.rue", source = """
 pub fn value() -> i32 { 1 }
@@ -37,7 +37,7 @@ compile_fail = true
 error_contains = ["E0206", "<module>"]
 files = [
     { path = "main.rue", source = """
-fn main() -> i32 { let h = @import("helper"); let arr = [h; 3]; 0 }
+fn main() -> i32 { let h = @import("helper.rue"); let arr = [h; 3]; 0 }
 """ },
     { path = "helper.rue", source = """
 pub fn value() -> i32 { 1 }

crates/rue-cli-tests/cases/assoc_fn_privacy.toml

@@ -18,7 +18,7 @@ description = "Cross-directory associated-function calls on a private struct are
 name = "cross_dir_unqualified_private_assoc_fn_rejected"
 files = [
     { path = "main.rue", source = """
-const lib = @import("sub/lib");
+const lib = @import("sub/lib.rue");
 
 fn main() -> i32 {
     let s = Secret.make();
@@ -41,7 +41,7 @@ error_contains = ["E0201", "undefined variable 'Secret'"]
 name = "cross_dir_qualified_private_assoc_fn_rejected"
 files = [
     { path = "main.rue", source = """
-const lib = @import("sub/lib");
+const lib = @import("sub/lib.rue");
 
 fn main() -> i32 {
     let s = lib.Secret.make();
@@ -63,7 +63,7 @@ error_contains = ["E0706", "struct `Secret` is private"]
 name = "cross_dir_pub_assoc_fn_allowed"
 files = [
     { path = "main.rue", source = """
-const lib = @import("sub/lib");
+const lib = @import("sub/lib.rue");
 
 fn main() -> i32 {
     let p = lib.Point.origin();
@@ -109,7 +109,7 @@ exit_code = 42
 name = "cross_dir_comptime_bound_assoc_fn_allowed"
 files = [
     { path = "main.rue", source = """
-const lib = @import("sub/lib");
+const lib = @import("sub/lib.rue");
 
 fn main() -> i32 {
     let P = lib.Point;

crates/rue-cli-tests/cases/byref_params.toml

@@ -440,7 +440,7 @@ description = "Passing the same variable to two inout parameters of a module mem
 files = [
     { path = "main.rue", source = """
 fn main() -> i32 {
-    let m = @import("mod_swap");
+    let m = @import("mod_swap.rue");
     let mut x = 1;
     m.swap(inout x, inout x);
     0
@@ -463,7 +463,7 @@ description = "Passing the same variable as both borrow and inout to a module me
 files = [
     { path = "main.rue", source = """
 fn main() -> i32 {
-    let m = @import("mod_obs");
+    let m = @import("mod_obs.rue");
     let mut x = 1;
     m.observe(borrow x, inout x)
 }
@@ -486,7 +486,7 @@ fn observe(borrow a: i32, inout b: i32) -> i32 {
     a + b
 }
 fn main() -> i32 {
-    let m = @import("helper");
+    let m = @import("helper.rue");
     let _ = m.one();
     let mut x = 5;
     observe(borrow x, inout x)
@@ -507,7 +507,7 @@ description = "Control: distinct variables passed by-ref to a module member call
 files = [
     { path = "main.rue", source = """
 fn main() -> i32 {
-    let m = @import("mod_swap");
+    let m = @import("mod_swap.rue");
     let mut x = 1;
     let mut y = 41;
     m.swap(inout x, inout y);

crates/rue-cli-tests/cases/comptime_value_params.toml

@@ -116,7 +116,7 @@ name = "module_member_call_with_comptime_param"
 description = "Calling a comptime-value function through a module object routes through specialization."
 files = [
     { path = "main.rue", source = """
-const util = @import("util");
+const util = @import("util.rue");
 fn main() -> i32 {
     @dbg(util.scale(5, 7));
     0

crates/rue-cli-tests/cases/const_init.toml

@@ -130,7 +130,7 @@ exit_code = 3
 name = "module_binding_exempt_from_annotation"
 files = [
     { path = "main.rue", source = """
-const cfg = @import("cfg");
+const cfg = @import("cfg.rue");
 const X: i32 = cfg.ANSWER;
 
 fn main() -> i32 {

crates/rue-cli-tests/cases/diagnostic_json.toml

@@ -138,7 +138,7 @@ JSON formatter shares with the text formatter (RUE-175).
 """
 files = [
   { path = "main.rue", source = """
-const helper = @import("helper");
+const helper = @import("helper.rue");
 
 fn main() -> i32 {
     let bad: i32 = true;

crates/rue-cli-tests/cases/emit_pipeline.toml

@@ -143,7 +143,7 @@ name = "emit_air_resolves_modules"
 description = "--emit skipped sema.set_file_paths, so module programs failed E0704 only under --emit (RUE-130 item 4)."
 files = [
     { path = "main.rue", source = """
-const utils = @import("utils");
+const utils = @import("utils.rue");
 
 fn main() -> i32 {
     utils.triple(2)

crates/rue-cli-tests/cases/float_literals.toml

@@ -131,7 +131,7 @@ points into the module that wrote it.
 files = [
     { path = "main.rue", source = """
 fn main() -> i32 {
-    let h = @import("helper");
+    let h = @import("helper.rue");
     h.scale()
 }
 """ },
@@ -152,7 +152,7 @@ description = "The gate follows the literal across the module boundary and repor
 files = [
     { path = "main.rue", source = """
 fn main() -> i32 {
-    let h = @import("helper");
+    let h = @import("helper.rue");
     h.scale()
 }
 """ },

crates/rue-cli-tests/cases/module_consts.toml

@@ -17,7 +17,7 @@ description = "Value consts as module members, module aliases, and const-context
 name = "value_const_as_module_member"
 files = [
     { path = "main.rue", source = """
-const math = @import("math");
+const math = @import("math.rue");
 
 fn main() -> i32 {
     math.ANSWER
@@ -33,8 +33,8 @@ exit_code = 42
 name = "same_named_value_consts_in_distinct_modules"
 files = [
     { path = "main.rue", source = """
-const a = @import("a");
-const b = @import("b");
+const a = @import("a.rue");
+const b = @import("b.rue");
 
 fn main() -> i32 {
     a.VALUE + b.VALUE
@@ -54,7 +54,7 @@ exit_code = 3
 name = "member_const_in_const_initializer"
 files = [
     { path = "main.rue", source = """
-const math = @import("math");
+const math = @import("math.rue");
 const COPY: i32 = math.ANSWER;
 
 fn main() -> i32 {
@@ -75,7 +75,7 @@ exit_code = 42
 name = "member_const_as_operator_operand"
 files = [
     { path = "main.rue", source = """
-const math = @import("math");
+const math = @import("math.rue");
 const A: i32 = 1 + math.ANSWER;
 const B: i32 = math.ANSWER * 2 - 4;
 
@@ -96,7 +96,7 @@ exit_code = 123
 name = "private_member_as_operator_operand_rejected"
 files = [
     { path = "main.rue", source = """
-const lib = @import("sub/lib");
+const lib = @import("sub/lib.rue");
 const A: i32 = 1 + lib.SECRET;
 
 fn main() -> i32 { A }
@@ -115,7 +115,7 @@ error_contains = ["E0706", "SECRET", "private"]
 name = "i64_member_const_keeps_width"
 files = [
     { path = "main.rue", source = """
-const cfg = @import("cfg");
+const cfg = @import("cfg.rue");
 
 fn main() -> i32 {
     if cfg.BIG / 1000000000 == 5 { 9 } else { 1 }
@@ -176,7 +176,7 @@ fn main() -> i32 {
 }
 """ },
     { path = "outer/_outer.rue", source = """
-pub const inner = @import("inner");
+pub const inner = @import("inner.rue");
 """ },
     { path = "outer/inner.rue", source = """
 pub fn value() -> i32 { 42 }
@@ -189,7 +189,7 @@ exit_code = 42
 name = "pub_member_const_across_directories"
 files = [
     { path = "main.rue", source = """
-const lib = @import("sub/lib");
+const lib = @import("sub/lib.rue");
 
 fn main() -> i32 {
     lib.LIMIT
@@ -206,7 +206,7 @@ exit_code = 17
 name = "private_member_const_rejected_at_use"
 files = [
     { path = "main.rue", source = """
-const lib = @import("sub/lib");
+const lib = @import("sub/lib.rue");
 
 fn main() -> i32 {
     lib.SECRET
@@ -225,7 +225,7 @@ error_contains = ["E0706", "SECRET", "private"]
 name = "private_member_const_rejected_in_const_context"
 files = [
     { path = "main.rue", source = """
-const lib = @import("sub/lib");
+const lib = @import("sub/lib.rue");
 const S: i32 = lib.SECRET;
 
 fn main() -> i32 { S }
@@ -243,7 +243,7 @@ error_contains = ["E0706", "SECRET", "private"]
 name = "private_member_const_same_directory_ok"
 files = [
     { path = "main.rue", source = """
-const lib = @import("lib");
+const lib = @import("lib.rue");
 
 fn main() -> i32 {
     lib.SECRET
@@ -262,7 +262,7 @@ name = "fn_member_const_alias_call"
 description = "A module-member function const creates a callable alias (spec 6.5:15), and calling the alias is equivalent to calling the function (spec 4.10:12)."
 files = [
     { path = "main.rue", source = """
-const abs_alias = @import("math").abs;
+const abs_alias = @import("math.rue").abs;
 
 fn main() -> i32 { abs_alias(0 - 42) }
 """ },
@@ -310,7 +310,7 @@ error_contains = ["E0434", "a function reference is not supported in const conte
 name = "unknown_member_still_e0707"
 files = [
     { path = "main.rue", source = """
-const math = @import("math");
+const math = @import("math.rue");
 const X: i32 = math.NOPE;
 
 fn main() -> i32 { 0 }
@@ -329,7 +329,7 @@ name = "value_const_member_through_local_let"
 files = [
     { path = "main.rue", source = """
 fn main() -> i32 {
-    let m = @import("math");
+    let m = @import("math.rue");
     @dbg(m.ANSWER);
     0
 }

crates/rue-cli-tests/cases/module_importer_relative.toml

@@ -20,8 +20,8 @@ description = "Relative @import resolves against the importing file's own direct
 name = "same_import_string_resolves_per_directory"
 files = [
     { path = "main.rue", source = """
-const a = @import("a/mod_a");
-const b = @import("b/mod_b");
+const a = @import("a/mod_a.rue");
+const b = @import("b/mod_b.rue");
 
 fn main() -> i32 {
     @dbg(a.a_val());
@@ -30,14 +30,14 @@ fn main() -> i32 {
 }
 """ },
     { path = "a/mod_a.rue", source = """
-const foo = @import("foo");
+const foo = @import("foo.rue");
 pub fn a_val() -> i32 { foo.a_foo() }
 """ },
     { path = "a/foo.rue", source = """
 pub fn a_foo() -> i32 { 10 }
 """ },
     { path = "b/mod_b.rue", source = """
-const foo = @import("foo");
+const foo = @import("foo.rue");
 pub fn b_val() -> i32 { foo.b_foo() }
 """ },
     { path = "b/foo.rue", source = """
@@ -74,8 +74,8 @@ exit_code = 15
 name = "file_module_and_facade_in_different_dirs_are_not_ambiguous"
 files = [
     { path = "main.rue", source = """
-const u1 = @import("sub/user1");
-const u2 = @import("facdir/user2");
+const u1 = @import("sub/user1.rue");
+const u2 = @import("facdir/user2.rue");
 
 fn main() -> i32 {
     @dbg(u1.one());
@@ -84,7 +84,7 @@ fn main() -> i32 {
 }
 """ },
     { path = "sub/user1.rue", source = """
-const foo = @import("foo");
+const foo = @import("foo.rue");
 pub fn one() -> i32 { foo.sfoo() }
 """ },
     { path = "sub/foo.rue", source = """
@@ -100,14 +100,19 @@ pub fn dfoo() -> i32 { 4 }
 ]
 stdout = "3\n4\n"
 
-# A genuine dual-entity ambiguity within ONE directory still errors (E0708):
-# both `foo.rue` and `foo/_foo.rue` sit next to the importer.
+# Both forms in ONE directory coexist (ADR-0078): the extensionless spelling
+# names the facade, the extensioned spelling names the file. E0708 is retired.
 [[case]]
-name = "genuine_single_dir_ambiguity_still_errors"
+name = "both_forms_in_one_dir_resolve_by_spelling"
 files = [
     { path = "main.rue", source = """
-const foo = @import("foo");
-fn main() -> i32 { foo.v_file() }
+const facade = @import("foo");
+const file = @import("foo.rue");
+fn main() -> i32 {
+    @dbg(file.v_file());
+    @dbg(facade.v_dir());
+    0
+}
 """ },
     { path = "foo.rue", source = """
 pub fn v_file() -> i32 { 1 }
@@ -116,5 +121,4 @@ pub fn v_file() -> i32 { 1 }
 pub fn v_dir() -> i32 { 2 }
 """ },
 ]
-compile_fail = true
-error_contains = ["E0708", "foo"]
+stdout = "1\n2\n"