Fix type predicate check circularity

src/compiler/checker.ts

@@ -8981,6 +8981,28 @@ namespace ts {
             return isLengthPushOrUnshift || isElementAssignment;
         }
 
+        function maybeTypePredicateCall(node: CallExpression) {
+            const links = getNodeLinks(node);
+            if (links.maybeTypePredicate === undefined) {
+                links.maybeTypePredicate = getMaybeTypePredicate(node);
+            }
+            return links.maybeTypePredicate;
+        }
+
+        function getMaybeTypePredicate(node: CallExpression) {
+            if (node.expression.kind !== SyntaxKind.SuperKeyword) {
+                const funcType = checkNonNullExpression(node.expression);
+                if (funcType !== silentNeverType) {
+                    const apparentType = getApparentType(funcType);
+                    if (apparentType !== unknownType) {
+                        const callSignatures = getSignaturesOfType(apparentType, SignatureKind.Call);
+                        return !!forEach(callSignatures, sig => sig.typePredicate);
+                    }
+                }
+            }
+            return false;
+        }
+
         function getFlowTypeOfReference(reference: Node, declaredType: Type, assumeInitialized: boolean, flowContainer: Node) {
             let key: string;
             if (!reference.flowNode || assumeInitialized && !(declaredType.flags & TypeFlags.Narrowable)) {
@@ -9495,7 +9517,7 @@ namespace ts {
             }
 
             function narrowTypeByTypePredicate(type: Type, callExpression: CallExpression, assumeTrue: boolean): Type {
-                if (!hasMatchingArgument(callExpression, reference)) {
+                if (!hasMatchingArgument(callExpression, reference) || !maybeTypePredicateCall(callExpression)) {
                     return type;
                 }
                 const signature = getResolvedSignature(callExpression);

src/compiler/types.ts

@@ -2668,6 +2668,7 @@ namespace ts {
         resolvedSignature?: Signature;    // Cached signature of signature node or call expression
         resolvedSymbol?: Symbol;          // Cached name resolution result
         resolvedIndexInfo?: IndexInfo;    // Cached indexing info resolution result
+        maybeTypePredicate?: boolean;     // Cached check whether call expression might reference a type predicate 
         enumMemberValue?: number;         // Constant value of enum member
         isVisible?: boolean;              // Is this node visible
         hasReportedStatementInAmbientContext?: boolean;  // Cache boolean if we report statements in ambient context

tests/baselines/reference/typePredicateInLoop.js

@@ -0,0 +1,38 @@
+//// [typePredicateInLoop.ts]
+// Repro from #12101
+
+interface Type {
+  type: number;
+}
+
+interface TypeExt extends Type {
+  arr: Type[];
+}
+
+const guard = (arg: Type): arg is TypeExt => arg.type === 1;
+const otherFunc = (arg1: Type, arg2: TypeExt): void => {};
+
+export function y(arg: Type): void {
+  if (guard(arg)) {
+    for (const ITEM of arg.arr) {
+      if (otherFunc(ITEM, arg)) {
+      }
+    }
+  }
+}
+
+//// [typePredicateInLoop.js]
+// Repro from #12101
+"use strict";
+var guard = function (arg) { return arg.type === 1; };
+var otherFunc = function (arg1, arg2) { };
+function y(arg) {
+    if (guard(arg)) {
+        for (var _i = 0, _a = arg.arr; _i < _a.length; _i++) {
+            var ITEM = _a[_i];
+            if (otherFunc(ITEM, arg)) {
+            }
+        }
+    }
+}
+exports.y = y;

tests/baselines/reference/typePredicateInLoop.symbols

@@ -0,0 +1,59 @@
+=== tests/cases/compiler/typePredicateInLoop.ts ===
+// Repro from #12101
+
+interface Type {
+>Type : Symbol(Type, Decl(typePredicateInLoop.ts, 0, 0))
+
+  type: number;
+>type : Symbol(Type.type, Decl(typePredicateInLoop.ts, 2, 16))
+}
+
+interface TypeExt extends Type {
+>TypeExt : Symbol(TypeExt, Decl(typePredicateInLoop.ts, 4, 1))
+>Type : Symbol(Type, Decl(typePredicateInLoop.ts, 0, 0))
+
+  arr: Type[];
+>arr : Symbol(TypeExt.arr, Decl(typePredicateInLoop.ts, 6, 32))
+>Type : Symbol(Type, Decl(typePredicateInLoop.ts, 0, 0))
+}
+
+const guard = (arg: Type): arg is TypeExt => arg.type === 1;
+>guard : Symbol(guard, Decl(typePredicateInLoop.ts, 10, 5))
+>arg : Symbol(arg, Decl(typePredicateInLoop.ts, 10, 15))
+>Type : Symbol(Type, Decl(typePredicateInLoop.ts, 0, 0))
+>arg : Symbol(arg, Decl(typePredicateInLoop.ts, 10, 15))
+>TypeExt : Symbol(TypeExt, Decl(typePredicateInLoop.ts, 4, 1))
+>arg.type : Symbol(Type.type, Decl(typePredicateInLoop.ts, 2, 16))
+>arg : Symbol(arg, Decl(typePredicateInLoop.ts, 10, 15))
+>type : Symbol(Type.type, Decl(typePredicateInLoop.ts, 2, 16))
+
+const otherFunc = (arg1: Type, arg2: TypeExt): void => {};
+>otherFunc : Symbol(otherFunc, Decl(typePredicateInLoop.ts, 11, 5))
+>arg1 : Symbol(arg1, Decl(typePredicateInLoop.ts, 11, 19))
+>Type : Symbol(Type, Decl(typePredicateInLoop.ts, 0, 0))
+>arg2 : Symbol(arg2, Decl(typePredicateInLoop.ts, 11, 30))
+>TypeExt : Symbol(TypeExt, Decl(typePredicateInLoop.ts, 4, 1))
+
+export function y(arg: Type): void {
+>y : Symbol(y, Decl(typePredicateInLoop.ts, 11, 58))
+>arg : Symbol(arg, Decl(typePredicateInLoop.ts, 13, 18))
+>Type : Symbol(Type, Decl(typePredicateInLoop.ts, 0, 0))
+
+  if (guard(arg)) {
+>guard : Symbol(guard, Decl(typePredicateInLoop.ts, 10, 5))
+>arg : Symbol(arg, Decl(typePredicateInLoop.ts, 13, 18))
+
+    for (const ITEM of arg.arr) {
+>ITEM : Symbol(ITEM, Decl(typePredicateInLoop.ts, 15, 14))
+>arg.arr : Symbol(TypeExt.arr, Decl(typePredicateInLoop.ts, 6, 32))
+>arg : Symbol(arg, Decl(typePredicateInLoop.ts, 13, 18))
+>arr : Symbol(TypeExt.arr, Decl(typePredicateInLoop.ts, 6, 32))
+
+      if (otherFunc(ITEM, arg)) {
+>otherFunc : Symbol(otherFunc, Decl(typePredicateInLoop.ts, 11, 5))
+>ITEM : Symbol(ITEM, Decl(typePredicateInLoop.ts, 15, 14))
+>arg : Symbol(arg, Decl(typePredicateInLoop.ts, 13, 18))
+      }
+    }
+  }
+}

tests/baselines/reference/typePredicateInLoop.types

@@ -0,0 +1,65 @@
+=== tests/cases/compiler/typePredicateInLoop.ts ===
+// Repro from #12101
+
+interface Type {
+>Type : Type
+
+  type: number;
+>type : number
+}
+
+interface TypeExt extends Type {
+>TypeExt : TypeExt
+>Type : Type
+
+  arr: Type[];
+>arr : Type[]
+>Type : Type
+}
+
+const guard = (arg: Type): arg is TypeExt => arg.type === 1;
+>guard : (arg: Type) => arg is TypeExt
+>(arg: Type): arg is TypeExt => arg.type === 1 : (arg: Type) => arg is TypeExt
+>arg : Type
+>Type : Type
+>arg : any
+>TypeExt : TypeExt
+>arg.type === 1 : boolean
+>arg.type : number
+>arg : Type
+>type : number
+>1 : 1
+
+const otherFunc = (arg1: Type, arg2: TypeExt): void => {};
+>otherFunc : (arg1: Type, arg2: TypeExt) => void
+>(arg1: Type, arg2: TypeExt): void => {} : (arg1: Type, arg2: TypeExt) => void
+>arg1 : Type
+>Type : Type
+>arg2 : TypeExt
+>TypeExt : TypeExt
+
+export function y(arg: Type): void {
+>y : (arg: Type) => void
+>arg : Type
+>Type : Type
+
+  if (guard(arg)) {
+>guard(arg) : boolean
+>guard : (arg: Type) => arg is TypeExt
+>arg : Type
+
+    for (const ITEM of arg.arr) {
+>ITEM : Type
+>arg.arr : Type[]
+>arg : TypeExt
+>arr : Type[]
+
+      if (otherFunc(ITEM, arg)) {
+>otherFunc(ITEM, arg) : void
+>otherFunc : (arg1: Type, arg2: TypeExt) => void
+>ITEM : Type
+>arg : TypeExt
+      }
+    }
+  }
+}

tests/cases/compiler/typePredicateInLoop.ts

@@ -0,0 +1,21 @@
+// Repro from #12101
+
+interface Type {
+  type: number;
+}
+
+interface TypeExt extends Type {
+  arr: Type[];
+}
+
+const guard = (arg: Type): arg is TypeExt => arg.type === 1;
+const otherFunc = (arg1: Type, arg2: TypeExt): void => {};
+
+export function y(arg: Type): void {
+  if (guard(arg)) {
+    for (const ITEM of arg.arr) {
+      if (otherFunc(ITEM, arg)) {
+      }
+    }
+  }
+}