From 168be30fe15215fade86eb67ad630feb6cf9308a Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Fri, 1 May 2020 16:29:30 -0700
Subject: [PATCH] Fix incorrect line text computation to stop comment directive
 searching Fixes #38289

---
 src/compiler/program.ts                       |  2 +-
 .../reference/ts-expect-error.errors.txt      | 19 ++++++-
 tests/baselines/reference/ts-expect-error.js  | 13 ++++-
 .../reference/ts-expect-error.symbols         | 21 ++++++++
 .../baselines/reference/ts-expect-error.types | 49 +++++++++++++++++++
 .../conformance/directives/ts-expect-error.ts |  7 +++
 6 files changed, 107 insertions(+), 4 deletions(-)

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index d06ee2cd0205a..437ec09e8b8ce 100644
--- a/src/compiler/program.ts
+++ b/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;
                 }
diff --git a/tests/baselines/reference/ts-expect-error.errors.txt b/tests/baselines/reference/ts-expect-error.errors.txt
index 7ffda9dbf1f9e..24e7ddd0d6edb 100644
--- a/tests/baselines/reference/ts-expect-error.errors.txt
+++ b/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';
-    
\ No newline at end of file
+    
+    // @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.
\ No newline at end of file
diff --git a/tests/baselines/reference/ts-expect-error.js b/tests/baselines/reference/ts-expect-error.js
index f37316d92b73c..88dc6ba3aa6ea 100644
--- a/tests/baselines/reference/ts-expect-error.js
+++ b/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
diff --git a/tests/baselines/reference/ts-expect-error.symbols b/tests/baselines/reference/ts-expect-error.symbols
index fec43e1eb2e01..434287cace708 100644
--- a/tests/baselines/reference/ts-expect-error.symbols
+++ b/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))
+
diff --git a/tests/baselines/reference/ts-expect-error.types b/tests/baselines/reference/ts-expect-error.types
index e338b276b7c5c..c010046d36fbe 100644
--- a/tests/baselines/reference/ts-expect-error.types
+++ b/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
+
diff --git a/tests/cases/conformance/directives/ts-expect-error.ts b/tests/cases/conformance/directives/ts-expect-error.ts
index 5baea77dc51e4..78c25dc4591f4 100644
--- a/tests/cases/conformance/directives/ts-expect-error.ts
+++ b/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
\ No newline at end of file