handle different arity of type params for interfaces

crates/stc_ts_errors/src/lib.rs

@@ -1560,6 +1560,11 @@ pub enum ErrorKind {
     NotDeclaredInSuperClass {
         span: Span,
     },
+
+    /// TS2428
+    InterfaceNonIdenticalTypeParams {
+        span: Span,
+    },
 }
 
 #[cfg(target_pointer_width = "64")]
@@ -2161,6 +2166,8 @@ impl ErrorKind {
 
             ErrorKind::NotDeclaredInSuperClass { .. } => 4113,
 
+            ErrorKind::InterfaceNonIdenticalTypeParams { .. } => 2428,
+
             _ => 0,
         }
     }

crates/stc_ts_file_analyzer/src/analyzer/decl_merging.rs

@@ -1,7 +1,7 @@
 use std::borrow::Cow;
 
 use fxhash::FxHashMap;
-use stc_ts_errors::{debug::dump_type_as_string, DebugExt};
+use stc_ts_errors::{debug::dump_type_as_string, DebugExt, ErrorKind};
 use stc_ts_types::{ClassDef, ClassMember, ClassProperty, Id, Interface, Method, Type, TypeElement, TypeParam, TypeParamDecl};
 use stc_utils::cache::Freeze;
 use swc_common::{Span, Spanned};
@@ -97,24 +97,37 @@ impl Analyzer<'_, '_> {
             }
 
             (Type::Interface(a), Type::Interface(bi)) => {
-                // TODO: Handle the number of type parameters.
                 let mut type_params = FxHashMap::default();
-                if let Some(b_tps) = &bi.type_params {
-                    if let Some(a_tp) = &a.type_params {
+
+                match (&a.type_params, &bi.type_params) {
+                    (Some(a_tps), Some(b_tps)) => {
+                        if a_tps.params.len() != b_tps.params.len() {
+                            self.storage
+                                .report(ErrorKind::InterfaceNonIdenticalTypeParams { span: a.span() }.into());
+                            self.storage
+                                .report(ErrorKind::InterfaceNonIdenticalTypeParams { span: b.span() }.into());
+                        }
+
                         for (idx, b_tp) in b_tps.params.iter().enumerate() {
                             type_params.insert(
                                 b_tp.name.clone(),
                                 Type::Param(TypeParam {
-                                    span: a_tp.span,
-                                    name: a_tp.params[idx].name.clone(),
+                                    span: a_tps.span,
+                                    name: a_tps.params.get(idx).unwrap_or(b_tp).name.clone(),
                                     constraint: None,
                                     default: None,
                                     metadata: Default::default(),
                                     tracker: Default::default(),
                                 }),
                             );
                         }
-                    } else {
+                    }
+                    (None, Some(b_tps)) => {
+                        self.storage
+                            .report(ErrorKind::InterfaceNonIdenticalTypeParams { span: a.span() }.into());
+                        self.storage
+                            .report(ErrorKind::InterfaceNonIdenticalTypeParams { span: b.span() }.into());
+
                         for (idx, b_tp) in b_tps.params.iter().enumerate() {
                             type_params.insert(
                                 b_tp.name.clone(),
@@ -129,7 +142,15 @@ impl Analyzer<'_, '_> {
                             );
                         }
                     }
+                    (Some(a_tps), None) => {
+                        self.storage
+                            .report(ErrorKind::InterfaceNonIdenticalTypeParams { span: a.span() }.into());
+                        self.storage
+                            .report(ErrorKind::InterfaceNonIdenticalTypeParams { span: b.span() }.into());
+                    }
+                    (None, None) => {}
                 }
+
                 let b_ty = self.expand_type_params(&type_params, b, Default::default())?.freezed();
 
                 let mut new_members = a.body.clone();

crates/stc_ts_type_checker/tests/conformance.pass.txt

@@ -2450,6 +2450,7 @@ types/objectTypeLiteral/callSignatures/typeParameterUsedAsTypeParameterConstrain
 types/objectTypeLiteral/callSignatures/typeParameterUsedAsTypeParameterConstraint4.ts
 types/objectTypeLiteral/constructSignatures/constructSignaturesWithIdenticalOverloads.ts
 types/objectTypeLiteral/constructSignatures/constructSignaturesWithOverloads.ts
+types/objectTypeLiteral/constructSignatures/constructSignaturesWithOverloads2.ts
 types/objectTypeLiteral/constructSignatures/constructSignaturesWithOverloadsThatDifferOnlyByReturnType.ts
 types/objectTypeLiteral/indexSignatures/numericIndexingResults.ts
 types/objectTypeLiteral/indexSignatures/stringIndexingResults.ts

crates/stc_ts_type_checker/tests/conformance/interfaces/declarationMerging/genericAndNonGenericInterfaceWithTheSameName.error-diff.json

@@ -1,13 +1,9 @@
 {
   "required_errors": {
-    "TS2428": 6
+    "TS2428": 2
   },
   "required_error_lines": {
     "TS2428": [
-      3,
-      7,
-      12,
-      16,
       34,
       40
     ]

crates/stc_ts_type_checker/tests/conformance/interfaces/declarationMerging/genericAndNonGenericInterfaceWithTheSameName.stats.rust-debug

@@ -1,6 +1,6 @@
 Stats {
-    required_error: 6,
-    matched_error: 0,
+    required_error: 2,
+    matched_error: 4,
     extra_error: 0,
     panic: 0,
 }

crates/stc_ts_type_checker/tests/conformance/types/objectTypeLiteral/constructSignatures/constructSignaturesWithOverloads2.error-diff.json → crates/stc_ts_type_checker/tests/conformance/interfaces/declarationMerging/twoGenericInterfacesWithTheSameNameButDifferentArity.error-diff.json

@@ -4,8 +4,8 @@
   },
   "required_error_lines": {
     "TS2428": [
-      27,
-      32
+      32,
+      38
     ]
   },
   "extra_errors": {},

crates/stc_ts_type_checker/tests/conformance/interfaces/declarationMerging/twoGenericInterfacesWithTheSameNameButDifferentArity.stats.rust-debug

@@ -1,6 +1,6 @@
 Stats {
-    required_error: 6,
-    matched_error: 0,
+    required_error: 2,
+    matched_error: 4,
     extra_error: 0,
-    panic: 1,
+    panic: 0,
 }

crates/stc_ts_type_checker/tests/conformance/types/conditional/conditionalTypes1.error-diff.json

@@ -1,8 +1,9 @@
 {
   "required_errors": {
     "TS2322": 6,
+    "TS2540": 2,
     "TS2542": 1,
-    "TS2540": 1,
+    "TS2339": 1,
     "TS2403": 1
   },
   "required_error_lines": {
@@ -14,11 +15,15 @@
       109,
       111
     ],
+    "TS2540": [
+      137,
+      139
+    ],
     "TS2542": [
       138
     ],
-    "TS2540": [
-      139
+    "TS2339": [
+      140
     ],
     "TS2403": [
       266

crates/stc_ts_type_checker/tests/conformance/types/conditional/conditionalTypes1.stats.rust-debug

@@ -1,6 +1,6 @@
 Stats {
-    required_error: 9,
-    matched_error: 11,
+    required_error: 11,
+    matched_error: 9,
     extra_error: 3,
     panic: 0,
 }

crates/stc_ts_type_checker/tests/conformance/types/objectTypeLiteral/constructSignatures/constructSignaturesWithOverloads2.stats.rust-debug

@@ -1,6 +1,6 @@
 Stats {
-    required_error: 2,
-    matched_error: 0,
+    required_error: 0,
+    matched_error: 2,
     extra_error: 0,
     panic: 0,
 }

crates/stc_ts_type_checker/tests/conformance/types/objectTypeLiteral/indexSignatures/multipleNumericIndexers.error-diff.json

@@ -1,7 +1,6 @@
 {
   "required_errors": {
-    "TS2374": 12,
-    "TS2428": 2
+    "TS2374": 12
   },
   "required_error_lines": {
     "TS2374": [
@@ -17,10 +16,6 @@
       25,
       29,
       30
-    ],
-    "TS2428": [
-      8,
-      28
     ]
   },
   "extra_errors": {},

crates/stc_ts_type_checker/tests/conformance/types/objectTypeLiteral/indexSignatures/multipleNumericIndexers.stats.rust-debug

@@ -1,6 +1,6 @@
 Stats {
-    required_error: 14,
-    matched_error: 0,
+    required_error: 12,
+    matched_error: 2,
     extra_error: 0,
     panic: 0,
 }

crates/stc_ts_type_checker/tests/tsc-stats.rust-debug

@@ -1,6 +1,6 @@
 Stats {
-    required_error: 3704,
-    matched_error: 6330,
+    required_error: 3694,
+    matched_error: 6340,
     extra_error: 747,
-    panic: 73,
+    panic: 72,
 }