Fix incorrect line text computation to stop comment directive searching

Fixes #38289

src/compiler/program.ts

@@ -1803,7 +1803,7 @@ namespace ts {
                 }
 
                 // Stop searching if the line is not empty and not a comment
-                const lineText = file.text.slice(lineStarts[line - 1], lineStarts[line]).trim();
+                const lineText = file.text.slice(lineStarts[line], lineStarts[line + 1]).trim();
                 if (lineText !== "" && !/^(\s*)\/\/(.*)$/.test(lineText)) {
                     return -1;
                 }

tests/baselines/reference/ts-expect-error.errors.txt

@@ -1,9 +1,12 @@
 tests/cases/conformance/directives/ts-expect-error.ts(4,1): error TS2578: Unused '@ts-expect-error' directive.
 tests/cases/conformance/directives/ts-expect-error.ts(10,1): error TS2578: Unused '@ts-expect-error' directive.
 tests/cases/conformance/directives/ts-expect-error.ts(13,5): error TS2322: Type '"nope"' is not assignable to type 'number'.
+tests/cases/conformance/directives/ts-expect-error.ts(19,2): error TS2367: This condition will always return 'false' since the types 'true' and 'false' have no overlap.
+tests/cases/conformance/directives/ts-expect-error.ts(21,2): error TS2367: This condition will always return 'false' since the types 'true' and 'false' have no overlap.
+tests/cases/conformance/directives/ts-expect-error.ts(22,2): error TS2367: This condition will always return 'false' since the types 'true' and 'false' have no overlap.
 
 
-==== tests/cases/conformance/directives/ts-expect-error.ts (3 errors) ====
+==== tests/cases/conformance/directives/ts-expect-error.ts (6 errors) ====
     // @ts-expect-error additional commenting
     var invalidCommentedFancy: number = 'nope';
     
@@ -25,4 +28,16 @@ tests/cases/conformance/directives/ts-expect-error.ts(13,5): error TS2322: Type
 !!! error TS2322: Type '"nope"' is not assignable to type 'number'.
     
     var validPlain: string = 'nope';
-    
+    
+    // @ts-expect-error
+    (({ a: true } as const).a === false); // <-- compiles (as expected via comment)
+    (({ a: true } as const).a === false); // Should error
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2367: This condition will always return 'false' since the types 'true' and 'false' have no overlap.
+    
+    (({ a: true } as const).a === false); // error
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2367: This condition will always return 'false' since the types 'true' and 'false' have no overlap.
+    (({ a: true } as const).a === false); // error
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2367: This condition will always return 'false' since the types 'true' and 'false' have no overlap.

tests/baselines/reference/ts-expect-error.js

@@ -14,7 +14,13 @@ var validCommentedPlain: string = 'nope';
 var invalidPlain: number = 'nope';
 
 var validPlain: string = 'nope';
-
+
+// @ts-expect-error
+(({ a: true } as const).a === false); // <-- compiles (as expected via comment)
+(({ a: true } as const).a === false); // Should error
+
+(({ a: true } as const).a === false); // error
+(({ a: true } as const).a === false); // error
 
 //// [ts-expect-error.js]
 // @ts-expect-error additional commenting
@@ -27,3 +33,8 @@ var invalidCommentedPlain = 'nope';
 var validCommentedPlain = 'nope';
 var invalidPlain = 'nope';
 var validPlain = 'nope';
+// @ts-expect-error
+({ a: true }.a === false); // <-- compiles (as expected via comment)
+({ a: true }.a === false); // Should error
+({ a: true }.a === false); // error
+({ a: true }.a === false); // error

tests/baselines/reference/ts-expect-error.symbols

@@ -21,3 +21,24 @@ var invalidPlain: number = 'nope';
 var validPlain: string = 'nope';
 >validPlain : Symbol(validPlain, Decl(ts-expect-error.ts, 14, 3))
 
+// @ts-expect-error
+(({ a: true } as const).a === false); // <-- compiles (as expected via comment)
+>({ a: true } as const).a : Symbol(a, Decl(ts-expect-error.ts, 17, 3))
+>a : Symbol(a, Decl(ts-expect-error.ts, 17, 3))
+>a : Symbol(a, Decl(ts-expect-error.ts, 17, 3))
+
+(({ a: true } as const).a === false); // Should error
+>({ a: true } as const).a : Symbol(a, Decl(ts-expect-error.ts, 18, 3))
+>a : Symbol(a, Decl(ts-expect-error.ts, 18, 3))
+>a : Symbol(a, Decl(ts-expect-error.ts, 18, 3))
+
+(({ a: true } as const).a === false); // error
+>({ a: true } as const).a : Symbol(a, Decl(ts-expect-error.ts, 20, 3))
+>a : Symbol(a, Decl(ts-expect-error.ts, 20, 3))
+>a : Symbol(a, Decl(ts-expect-error.ts, 20, 3))
+
+(({ a: true } as const).a === false); // error
+>({ a: true } as const).a : Symbol(a, Decl(ts-expect-error.ts, 21, 3))
+>a : Symbol(a, Decl(ts-expect-error.ts, 21, 3))
+>a : Symbol(a, Decl(ts-expect-error.ts, 21, 3))
+

tests/baselines/reference/ts-expect-error.types

@@ -27,3 +27,52 @@ var validPlain: string = 'nope';
 >validPlain : string
 >'nope' : "nope"
 
+// @ts-expect-error
+(({ a: true } as const).a === false); // <-- compiles (as expected via comment)
+>(({ a: true } as const).a === false) : boolean
+>({ a: true } as const).a === false : boolean
+>({ a: true } as const).a : true
+>({ a: true } as const) : { readonly a: true; }
+>{ a: true } as const : { readonly a: true; }
+>{ a: true } : { readonly a: true; }
+>a : true
+>true : true
+>a : true
+>false : false
+
+(({ a: true } as const).a === false); // Should error
+>(({ a: true } as const).a === false) : boolean
+>({ a: true } as const).a === false : boolean
+>({ a: true } as const).a : true
+>({ a: true } as const) : { readonly a: true; }
+>{ a: true } as const : { readonly a: true; }
+>{ a: true } : { readonly a: true; }
+>a : true
+>true : true
+>a : true
+>false : false
+
+(({ a: true } as const).a === false); // error
+>(({ a: true } as const).a === false) : boolean
+>({ a: true } as const).a === false : boolean
+>({ a: true } as const).a : true
+>({ a: true } as const) : { readonly a: true; }
+>{ a: true } as const : { readonly a: true; }
+>{ a: true } : { readonly a: true; }
+>a : true
+>true : true
+>a : true
+>false : false
+
+(({ a: true } as const).a === false); // error
+>(({ a: true } as const).a === false) : boolean
+>({ a: true } as const).a === false : boolean
+>({ a: true } as const).a : true
+>({ a: true } as const) : { readonly a: true; }
+>{ a: true } as const : { readonly a: true; }
+>{ a: true } : { readonly a: true; }
+>a : true
+>true : true
+>a : true
+>false : false
+

tests/cases/conformance/directives/ts-expect-error.ts

@@ -13,3 +13,10 @@ var validCommentedPlain: string = 'nope';
 var invalidPlain: number = 'nope';
 
 var validPlain: string = 'nope';
+
+// @ts-expect-error
+(({ a: true } as const).a === false); // <-- compiles (as expected via comment)
+(({ a: true } as const).a === false); // Should error
+
+(({ a: true } as const).a === false); // error
+(({ a: true } as const).a === false); // error