Merge pull request #6745 from Microsoft/fix6637

Fix6637

Author: yuit

src/compiler/sourcemap.ts

@@ -16,6 +16,14 @@ namespace ts {
     }
 
     let nullSourceMapWriter: SourceMapWriter;
+    // Used for initialize lastEncodedSourceMapSpan and reset lastEncodedSourceMapSpan when updateLastEncodedAndRecordedSpans
+    const defaultLastEncodedSourceMapSpan: SourceMapSpan = {
+        emittedLine: 1,
+        emittedColumn: 1,
+        sourceLine: 1,
+        sourceColumn: 1,
+        sourceIndex: 0
+    };
 
     export function getNullSourceMapWriter(): SourceMapWriter {
         if (nullSourceMapWriter === undefined) {
@@ -79,13 +87,7 @@ namespace ts {
 
             // Last recorded and encoded spans
             lastRecordedSourceMapSpan = undefined;
-            lastEncodedSourceMapSpan = {
-                emittedLine: 1,
-                emittedColumn: 1,
-                sourceLine: 1,
-                sourceColumn: 1,
-                sourceIndex: 0
-            };
+            lastEncodedSourceMapSpan = defaultLastEncodedSourceMapSpan;
             lastEncodedNameIndex = 0;
 
             // Initialize source map data
@@ -159,10 +161,12 @@ namespace ts {
                 // Pop sourceMapDecodedMappings to remove last entry
                 sourceMapData.sourceMapDecodedMappings.pop();
 
-                // Change the last encoded source map
+                // Point the lastEncodedSourceMapSpace to the previous encoded sourceMapSpan
+                // If the list is empty which indicates that we are at the beginning of the file,
+                // we have to reset it to default value (same value when we first initialize sourceMapWriter)
                 lastEncodedSourceMapSpan = sourceMapData.sourceMapDecodedMappings.length ?
                     sourceMapData.sourceMapDecodedMappings[sourceMapData.sourceMapDecodedMappings.length - 1] :
-                    undefined;
+                    defaultLastEncodedSourceMapSpan;
 
                 // TODO: Update lastEncodedNameIndex 
                 // Since we dont support this any more, lets not worry about it right now.

tests/baselines/reference/sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.js

@@ -0,0 +1,24 @@
+===================================================================
+JsFile: sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.js
+mapUrl: sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.js.map
+sourceRoot: 
+sources: sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.ts
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.js
+sourceFile:sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.ts
+-------------------------------------------------------------------
+>>>var x = [1, 2][0];
+1 >
+2 >^^^^^^^^^^^^^^^^^
+3 >                 ^
+4 >                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >var [
+2 >x
+3 >                 ] = [1, 2];
+1 >Emitted(1, 1) Source(2, 6) + SourceIndex(0)
+2 >Emitted(1, 18) Source(2, 7) + SourceIndex(0)
+3 >Emitted(1, 19) Source(2, 18) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.js.map

tests/baselines/reference/sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.js.map

@@ -0,0 +1,5 @@
+=== tests/cases/compiler/sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.ts ===
+
+var [x] = [1, 2];
+>x : Symbol(x, Decl(sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.ts, 1, 5))
+

tests/baselines/reference/sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.sourcemap.txt

@@ -0,0 +1,8 @@
+=== tests/cases/compiler/sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.ts ===
+
+var [x] = [1, 2];
+>x : number
+>[1, 2] : [number, number]
+>1 : number
+>2 : number
+

tests/baselines/reference/sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.symbols

@@ -0,0 +1,52 @@
+===================================================================
+JsFile: sourceMapValidationDestructuringVariableStatementArrayBindingPattern5.js
+mapUrl: sourceMapValidationDestructuringVariableStatementArrayBindingPattern5.js.map
+sourceRoot: 
+sources: sourceMapValidationDestructuringVariableStatementArrayBindingPattern5.ts
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/sourceMapValidationDestructuringVariableStatementArrayBindingPattern5.js
+sourceFile:sourceMapValidationDestructuringVariableStatementArrayBindingPattern5.ts
+-------------------------------------------------------------------
+>>>var x = [1, 2][0];
+1 >
+2 >^^^^^^^^^^^^^^^^^
+3 >                 ^
+4 >                  ^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >var [
+2 >x
+3 >                 ] = [1, 2];
+1 >Emitted(1, 1) Source(2, 6) + SourceIndex(0)
+2 >Emitted(1, 18) Source(2, 7) + SourceIndex(0)
+3 >Emitted(1, 19) Source(2, 18) + SourceIndex(0)
+---
+>>>var _a = [1, 2], y = _a[0], z = _a[1];
+1->
+2 >^^^^
+3 >    ^^^^^^^^^^^
+4 >               ^^
+5 >                 ^^^^^^^^^
+6 >                          ^^
+7 >                            ^^^^^^^^^
+8 >                                     ^
+9 >                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1->
+  >
+2 >
+3 >    var [y, z] = [1, 2]
+4 >               
+5 >                 y
+6 >                          , 
+7 >                            z
+8 >                                     ] = [1, 2];
+1->Emitted(2, 1) Source(3, 1) + SourceIndex(0)
+2 >Emitted(2, 5) Source(3, 1) + SourceIndex(0)
+3 >Emitted(2, 16) Source(3, 20) + SourceIndex(0)
+4 >Emitted(2, 18) Source(3, 6) + SourceIndex(0)
+5 >Emitted(2, 27) Source(3, 7) + SourceIndex(0)
+6 >Emitted(2, 29) Source(3, 9) + SourceIndex(0)
+7 >Emitted(2, 38) Source(3, 10) + SourceIndex(0)
+8 >Emitted(2, 39) Source(3, 21) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=sourceMapValidationDestructuringVariableStatementArrayBindingPattern5.js.map

tests/baselines/reference/sourceMapValidationDestructuringVariableStatementArrayBindingPattern4.types

@@ -0,0 +1,9 @@
+=== tests/cases/compiler/sourceMapValidationDestructuringVariableStatementArrayBindingPattern5.ts ===
+
+var [x] = [1, 2];
+>x : Symbol(x, Decl(sourceMapValidationDestructuringVariableStatementArrayBindingPattern5.ts, 1, 5))
+
+var [y, z] = [1, 2];
+>y : Symbol(y, Decl(sourceMapValidationDestructuringVariableStatementArrayBindingPattern5.ts, 2, 5))
+>z : Symbol(z, Decl(sourceMapValidationDestructuringVariableStatementArrayBindingPattern5.ts, 2, 7))
+