* checker.ts: Remove null check on symbols
* tsserverProjectSystem.ts: add two tests
* client.ts, completions.ts, types.ts: Add codeActions member to CompletionEntryDetails
* protocol.ts, session.ts: Add codeActions member to CompletionEntryDetails protocol
* protocol.ts, session.ts, types.ts: add hasAction to CompletionEntry
* session.ts, services.ts, types.ts: Add formattingOptions parameter to getCompletionEntryDetails
* completions.ts: define SymbolOriginInfo type
* completions.ts, services.ts: Add allSourceFiles parameter to getCompletionsAtPosition
* completions.ts, services.ts: Plumb allSourceFiles into new function getSymbolsFromOtherSourceFileExports inside getCompletionData
* completions.ts: add symbolToOriginInfoMap parameter to getCompletionEntriesFromSymbols and to return value of getCompletionData
* utilities.ts: Add getOtherModuleSymbols, getUniqueSymbolIdAsString, getUniqueSymbolId
* completions.ts: Set CompletionEntry.hasAction when symbol is found in symbolToOriginInfoMap (meaning there's an import action)
* completions.ts: Populate list with possible exports (implement getSymbolsFromOtherSourceFileExports)
* completions.ts, services.ts: Plumb host and rulesProvider into getCompletionEntryDetails
* completions.ts: Add TODO comment
* importFixes.ts: Add types ImportDeclarationMap and ImportCodeFixContext
* Move getImportDeclarations into getCodeActionForImport, immediately after the implementation
* importFixes.ts: Move createChangeTracker into getCodeActionForImport, immediately after getImportDeclarations
* importFixes.ts: Add convertToImportCodeFixContext function and reference it from the getCodeActions lambda
* importFixes.ts: Add context: ImportCodeFixContext parameter to getCodeActionForImport, update call sites, destructure it, use compilerOptions in getModuleSpecifierForNewImport
* importFixes.ts: Remove moduleSymbol parameter from getImportDeclarations and use the ambient one
* importFixes.ts: Use cachedImportDeclarations from context in getCodeActionForImport
* importFixes.ts: Move createCodeAction out, immediately above convertToImportCodeFixContext
* Move the declaration for lastImportDeclaration out of the getCodeActions lambda into getCodeActionForImport
* importFixes.ts: Use symbolToken in getCodeActionForImport
* importFixes.ts: Remove useCaseSensitiveFileNames altogether from getCodeActions lambda
* importFixes.ts: Remove local getUniqueSymbolId function and add checker parameter to calls to it
* importFixes.ts: Move getCodeActionForImport out into an export, immediately below convertToImportCodeFixContext
* completions.ts: In getCompletionEntryDetails, if there's symbolOriginInfo, call getCodeActionForImport
* importFixes.ts: Create and use importFixContext within getCodeActions lambda
* importFixes.ts: Use local newLineCharacter instead of context.newLineCharacter in getCodeActionForImport
* importFixes.ts: Use local host instead of context.host in getCodeActionForImport
* importFixes.ts: Remove dummy getCanonicalFileName line
* Filter symbols after gathering exports instead of before
* Lint
* Test, fix bugs, refactor
* Suggestions from code review
* Update api baseline
* Fix bug if previousToken is not an Identifier
* Replace `startsWith` with `stringContainsCharactersInOrder`
* Explicitly avoid canonicalizing paths during configuration handling
* Extract usage of identity in commandLineParser into single function, use identity in checker
* Add 'name' property to Identifier
* Rename to unescapedText
* Rename 'id.text' to 'id.escapedText'
* Rename 'id.unescapedText' to 'id.text'
* Make escapeIdentifier and unescapeIdentifier do nothing
* Created a branded type for escaped strings
Then flowed it throughout the compiler, finding and fixing a handful of
bugs relating to underscore-prefixed identifiers in the process.
Includes a test for two cases noticed - diagnostics from conflicting
symbols from export *'s, and enum with underscore prefixed member emit.
* Correctly double underscores WRT mapped types
* Add fourslash tests for other fixed issues
* use function call over cast
* Update forEachEntry type accuracy
* Just use escaped names for ActiveLabel
* Remove casts from getPropertyNameForPropertyNameNode
* This pattern has occurred a few times, could use a helper function.
* Remove duplicated helper
* Remove unneeded check, use helper
* Identifiers list is no longer escaped strings
* Extract repeated string-getting code into helper
* Rename type and associated functions
* Make getName() return UnderscoreEscapedString, add getUnescapedName()
* Add list of internal symbol names to escaped string type to cut back on casting
* Remove outdated comments
* Reassign interned values to nodes, just in case
* Swap to string enum
* Add deprecated aliases to escapeIdentifier and unescapeIdentifier
* Add temp var
* Remove unsafe casts
* Rename escaped string type as per @sandersn's suggestion, fix string enum usages
* Reorganize double underscore tests
* Remove jfreeman from TODO
* Remove unneeded parenthesis
1. convertToArray is a duplicate of arrayFrom
2. inferFromParameterTypes delegates immediately to inferFromTypes
3. One usage of arrayFrom instantiated a whole iterator only to take the
first element, which is the same as calling `next`.
