Extend isTupleLikeType to also check if .length is a number literal type (#52617)

Author: Andarist

src/compiler/checker.ts

@@ -23303,7 +23303,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     }
 
     function isTupleLikeType(type: Type): boolean {
-        return isTupleType(type) || !!getPropertyOfType(type, "0" as __String);
+        let lengthType;
+        return isTupleType(type) ||
+            !!getPropertyOfType(type, "0" as __String) ||
+            isArrayLikeType(type) && !!(lengthType = getTypeOfPropertyOfType(type, "length" as __String)) && everyType(lengthType, t => !!(t.flags & TypeFlags.NumberLiteral));
     }
 
     function isArrayOrTupleLikeType(type: Type): boolean {

tests/baselines/reference/contextualTypeWithTuple.errors.txt

@@ -68,4 +68,15 @@ contextualTypeWithTuple.ts(25,1): error TS2322: Type '[number, string | number]'
 !!! error TS2322: Type '[number, string | number]' is not assignable to type '[number, string]'.
 !!! error TS2322:   Type at position 1 in source is not compatible with type at position 1 in target.
 !!! error TS2322:     Type 'string | number' is not assignable to type 'string'.
-!!! error TS2322:       Type 'number' is not assignable to type 'string'.
+!!! error TS2322:       Type 'number' is not assignable to type 'string'.
+    
+    // repro from #29311
+    type test1 = [...number[]]
+    type fixed1 = test1 & { length: 2 }
+    let var1: fixed1 = [0, 0]
+    
+    // #52551
+    type EmptyTuple = []
+    interface MyEmptyTuple extends EmptyTuple { extraInfo?: any; }
+    const withExtra: MyEmptyTuple = []
+    

tests/baselines/reference/contextualTypeWithTuple.js

@@ -25,7 +25,18 @@ var strStrTuple: [string, string] = ["foo", "bar", 5];
 unionTuple = unionTuple1;
 unionTuple = unionTuple2;
 unionTuple2 = unionTuple;
-numStrTuple = unionTuple3;
+numStrTuple = unionTuple3;
+
+// repro from #29311
+type test1 = [...number[]]
+type fixed1 = test1 & { length: 2 }
+let var1: fixed1 = [0, 0]
+
+// #52551
+type EmptyTuple = []
+interface MyEmptyTuple extends EmptyTuple { extraInfo?: any; }
+const withExtra: MyEmptyTuple = []
+
 
 //// [contextualTypeWithTuple.js]
 // no error
@@ -58,3 +69,5 @@ unionTuple = unionTuple1;
 unionTuple = unionTuple2;
 unionTuple2 = unionTuple;
 numStrTuple = unionTuple3;
+var var1 = [0, 0];
+var withExtra = [];

tests/baselines/reference/contextualTypeWithTuple.symbols

@@ -82,3 +82,29 @@ numStrTuple = unionTuple3;
 >numStrTuple : Symbol(numStrTuple, Decl(contextualTypeWithTuple.ts, 1, 3))
 >unionTuple3 : Symbol(unionTuple3, Decl(contextualTypeWithTuple.ts, 11, 3))
 
+// repro from #29311
+type test1 = [...number[]]
+>test1 : Symbol(test1, Decl(contextualTypeWithTuple.ts, 24, 26))
+
+type fixed1 = test1 & { length: 2 }
+>fixed1 : Symbol(fixed1, Decl(contextualTypeWithTuple.ts, 27, 26))
+>test1 : Symbol(test1, Decl(contextualTypeWithTuple.ts, 24, 26))
+>length : Symbol(length, Decl(contextualTypeWithTuple.ts, 28, 23))
+
+let var1: fixed1 = [0, 0]
+>var1 : Symbol(var1, Decl(contextualTypeWithTuple.ts, 29, 3))
+>fixed1 : Symbol(fixed1, Decl(contextualTypeWithTuple.ts, 27, 26))
+
+// #52551
+type EmptyTuple = []
+>EmptyTuple : Symbol(EmptyTuple, Decl(contextualTypeWithTuple.ts, 29, 25))
+
+interface MyEmptyTuple extends EmptyTuple { extraInfo?: any; }
+>MyEmptyTuple : Symbol(MyEmptyTuple, Decl(contextualTypeWithTuple.ts, 32, 20))
+>EmptyTuple : Symbol(EmptyTuple, Decl(contextualTypeWithTuple.ts, 29, 25))
+>extraInfo : Symbol(MyEmptyTuple.extraInfo, Decl(contextualTypeWithTuple.ts, 33, 43))
+
+const withExtra: MyEmptyTuple = []
+>withExtra : Symbol(withExtra, Decl(contextualTypeWithTuple.ts, 34, 5))
+>MyEmptyTuple : Symbol(MyEmptyTuple, Decl(contextualTypeWithTuple.ts, 32, 20))
+

tests/baselines/reference/contextualTypeWithTuple.types

@@ -128,3 +128,28 @@ numStrTuple = unionTuple3;
 >numStrTuple : [number, string]
 >unionTuple3 : [number, string | number]
 
+// repro from #29311
+type test1 = [...number[]]
+>test1 : number[]
+
+type fixed1 = test1 & { length: 2 }
+>fixed1 : test1 & { length: 2; }
+>length : 2
+
+let var1: fixed1 = [0, 0]
+>var1 : fixed1
+>[0, 0] : [number, number]
+>0 : 0
+>0 : 0
+
+// #52551
+type EmptyTuple = []
+>EmptyTuple : []
+
+interface MyEmptyTuple extends EmptyTuple { extraInfo?: any; }
+>extraInfo : any
+
+const withExtra: MyEmptyTuple = []
+>withExtra : MyEmptyTuple
+>[] : []
+

tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts

@@ -22,4 +22,14 @@ var strStrTuple: [string, string] = ["foo", "bar", 5];
 unionTuple = unionTuple1;
 unionTuple = unionTuple2;
 unionTuple2 = unionTuple;
-numStrTuple = unionTuple3;
+numStrTuple = unionTuple3;
+
+// repro from #29311
+type test1 = [...number[]]
+type fixed1 = test1 & { length: 2 }
+let var1: fixed1 = [0, 0]
+
+// #52551
+type EmptyTuple = []
+interface MyEmptyTuple extends EmptyTuple { extraInfo?: any; }
+const withExtra: MyEmptyTuple = []