Minor fix for assertion predicates (microsoft#38710)

Author: jack-williams

src/compiler/checker.ts

@@ -20474,7 +20474,7 @@ namespace ts {
                     const signature = getEffectsSignature((<FlowCall>flow).node);
                     if (signature) {
                         const predicate = getTypePredicateOfSignature(signature);
-                        if (predicate && predicate.kind === TypePredicateKind.AssertsIdentifier) {
+                        if (predicate && predicate.kind === TypePredicateKind.AssertsIdentifier && !predicate.type) {
                             const predicateArgument = (<FlowCall>flow).node.arguments[predicate.parameterIndex];
                             if (predicateArgument && isFalseExpression(predicateArgument)) {
                                 return false;

tests/baselines/reference/assertionTypePredicates1.errors.txt

@@ -1,18 +1,18 @@
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(39,9): error TS7027: Unreachable code detected.
 tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(43,9): error TS7027: Unreachable code detected.
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(87,9): error TS7027: Unreachable code detected.
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(122,9): error TS7027: Unreachable code detected.
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(137,9): error TS7027: Unreachable code detected.
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(153,37): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(154,37): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(155,37): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(158,15): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(159,15): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(160,15): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(161,15): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(166,5): error TS2775: Assertions require every name in the call target to be declared with an explicit type annotation.
-tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(168,5): error TS2776: Assertions require the call target to be an identifier or qualified name.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(47,9): error TS7027: Unreachable code detected.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(91,9): error TS7027: Unreachable code detected.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(126,9): error TS7027: Unreachable code detected.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(141,9): error TS7027: Unreachable code detected.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(157,37): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(158,37): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(159,37): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(162,15): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(163,15): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(164,15): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(165,15): error TS1228: A type predicate is only allowed in return type position for functions and methods.
 tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(170,5): error TS2775: Assertions require every name in the call target to be declared with an explicit type annotation.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(172,5): error TS2776: Assertions require the call target to be an identifier or qualified name.
+tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(174,5): error TS2775: Assertions require every name in the call target to be declared with an explicit type annotation.
 
 
 ==== tests/cases/conformance/controlFlow/assertionTypePredicates1.ts (15 errors) ====
@@ -46,6 +46,10 @@ tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(170,5): error TS
             assertIsArrayOfStrings(x);
             x[0].length;
         }
+        if (!!true) {
+            assertIsArrayOfStrings(false);
+            x;
+        }
         if (!!true) {
             assert(x === undefined || typeof x === "string");
             x;  // string | undefined
@@ -208,7 +212,7 @@ tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(170,5): error TS
         assert(typeof x === "string");  // Error
         ~~~~~~
 !!! error TS2775: Assertions require every name in the call target to be declared with an explicit type annotation.
-!!! related TS2782 tests/cases/conformance/controlFlow/assertionTypePredicates1.ts:165:11: 'assert' needs an explicit type annotation.
+!!! related TS2782 tests/cases/conformance/controlFlow/assertionTypePredicates1.ts:169:11: 'assert' needs an explicit type annotation.
         const a = [assert];
         a[0](typeof x === "string");  // Error
         ~~~~
@@ -217,7 +221,7 @@ tests/cases/conformance/controlFlow/assertionTypePredicates1.ts(170,5): error TS
         t1.assert(typeof x === "string");  // Error
         ~~~~~~~~~
 !!! error TS2775: Assertions require every name in the call target to be declared with an explicit type annotation.
-!!! related TS2782 tests/cases/conformance/controlFlow/assertionTypePredicates1.ts:169:11: 't1' needs an explicit type annotation.
+!!! related TS2782 tests/cases/conformance/controlFlow/assertionTypePredicates1.ts:173:11: 't1' needs an explicit type annotation.
         const t2: Test = new Test();
         t2.assert(typeof x === "string");
     }

tests/baselines/reference/assertionTypePredicates1.js

@@ -29,6 +29,10 @@ function f01(x: unknown) {
         assertIsArrayOfStrings(x);
         x[0].length;
     }
+    if (!!true) {
+        assertIsArrayOfStrings(false);
+        x;
+    }
     if (!!true) {
         assert(x === undefined || typeof x === "string");
         x;  // string | undefined
@@ -229,6 +233,10 @@ function f01(x) {
         assertIsArrayOfStrings(x);
         x[0].length;
     }
+    if (!!true) {
+        assertIsArrayOfStrings(false);
+        x;
+    }
     if (!!true) {
         assert(x === undefined || typeof x === "string");
         x; // string | undefined