use absolute path as key to store files, correctly handle scenarios w…

src/compiler/commandLineParser.ts

@@ -247,7 +247,12 @@ namespace ts {
             },
             description: Diagnostics.Specifies_module_resolution_strategy_Colon_node_Node_js_or_classic_TypeScript_pre_1_6,
             error: Diagnostics.Argument_for_moduleResolution_option_must_be_node_or_classic,
-        }
+        },
+        {
+            name: "forceConsistentCasingInFileNames",
+            type: "boolean",
+            description: Diagnostics.Disallow_inconsistently_cased_references_to_the_same_file
+        },
     ];
 
     /* @internal */

src/compiler/diagnosticMessages.json

@@ -2298,7 +2298,10 @@
         "category": "Message",
         "code": 6072
     },
-
+    "Disallow inconsistently-cased references to the same file.": {
+        "category": "Message",
+        "code": 6073
+    },
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005

src/compiler/types.ts

@@ -2088,6 +2088,7 @@ namespace ts {
         experimentalDecorators?: boolean;
         emitDecoratorMetadata?: boolean;
         moduleResolution?: ModuleResolutionKind;
+        forceConsistentCasingInFileNames?: boolean;
         /* @internal */ stripInternal?: boolean;
 
         // Skip checking lib.d.ts to help speed up tests.

src/harness/harness.ts

@@ -921,7 +921,9 @@ namespace Harness {
             function register(file: { unitName: string; content: string; }) {
                 if (file.content !== undefined) {
                     let fileName = ts.normalizePath(file.unitName);
-                    filemap[getCanonicalFileName(fileName)] = createSourceFileAndAssertInvariants(fileName, file.content, scriptTarget);
+                    const sourceFile = createSourceFileAndAssertInvariants(fileName, file.content, scriptTarget);
+                    filemap[getCanonicalFileName(fileName)] = sourceFile;
+                    filemap[getCanonicalFileName(ts.getNormalizedAbsolutePath(fileName, getCurrentDirectory()))] = sourceFile;
                 }
             };
             inputFiles.forEach(register);

src/harness/projectsRunner.ts

@@ -127,7 +127,7 @@ class ProjectRunner extends RunnerBase {
         }
 
         function compileProjectFiles(moduleKind: ts.ModuleKind, getInputFiles: () => string[],
-            getSourceFileText: (fileName: string) => string,
+            getSourceFileTextImpl: (fileName: string) => string,
             writeFile: (fileName: string, data: string, writeByteOrderMark: boolean) => void): CompileProjectFilesResult {
 
             let program = ts.createProgram(getInputFiles(), createCompilerOptions(), createCompilerHost());
@@ -170,6 +170,11 @@ class ProjectRunner extends RunnerBase {
                 };
             }
 
+            function getSourceFileText(fileName: string): string {
+                const text = getSourceFileTextImpl(fileName);
+                return text !== undefined ? text : getSourceFileTextImpl(ts.getNormalizedAbsolutePath(fileName, getCurrentDirectory()));
+            }
+
             function getSourceFile(fileName: string, languageVersion: ts.ScriptTarget): ts.SourceFile {
                 let sourceFile: ts.SourceFile = undefined;
                 if (fileName === Harness.Compiler.defaultLibFileName) {
@@ -194,7 +199,7 @@ class ProjectRunner extends RunnerBase {
                     getCanonicalFileName: Harness.Compiler.getCanonicalFileName,
                     useCaseSensitiveFileNames: () => Harness.IO.useCaseSensitiveFileNames(),
                     getNewLine: () => Harness.IO.newLine(),
-                    fileExists: fileName => getSourceFile(fileName, ts.ScriptTarget.ES5) !== undefined,
+                    fileExists: fileName => fileName === Harness.Compiler.defaultLibFileName ||  getSourceFileText(fileName) !== undefined,
                     readFile: fileName => Harness.IO.readFile(fileName)
                 };
             }
@@ -318,7 +323,16 @@ class ProjectRunner extends RunnerBase {
                 return ts.map(allInputFiles, outputFile => outputFile.emittedFileName);
             }
             function getSourceFileText(fileName: string): string {
-                return ts.forEach(allInputFiles, inputFile => inputFile.emittedFileName === fileName ? inputFile.code : undefined);
+                for (const inputFile of allInputFiles) {
+                    const isMatchingFile = ts.isRootedDiskPath(fileName)
+                        ? ts.getNormalizedAbsolutePath(inputFile.emittedFileName, getCurrentDirectory()) === fileName
+                        : inputFile.emittedFileName === fileName;
+
+                    if (isMatchingFile) {
+                        return inputFile.code;
+                    }
+                }
+                return undefined;
             }
 
             function writeFile(fileName: string, data: string, writeByteOrderMark: boolean) {