Don’t add --crate-type to rust compiler options when explicitly specified by user (#8191)

Resolves #8186.

etc/config/rust.defaults.properties

@@ -1,5 +1,6 @@
 compilers=rustc
 supportsBinary=true
+supportsBinaryObject=true
 compilerType=rust
 demangler=c++filt
 demanglerArgs=--format=rust

lib/compilers/rust.ts

@@ -271,19 +271,22 @@ export class RustCompiler extends BaseCompiler {
         let options = ['-C', 'debuginfo=2', '-o', this.filename(outputFilename)];
 
         const userRequestedEmit = _.any(unwrap(userOptions), opt => opt.includes('--emit'));
+        const userRequestedCrateType = _.any(unwrap(userOptions), opt => opt.includes('--crate-type'));
+        const setCrateType = (options, type) =>
+            userRequestedCrateType ? options : options.concat(['--crate-type', type]);
         if (filters.binary) {
-            options = options.concat(['--crate-type', 'bin']);
+            options = setCrateType(options, 'bin');
             if (this.amd64linker) {
                 options = options.concat(`-Clinker=${this.amd64linker}`);
             }
         } else if (filters.binaryObject) {
-            options = options.concat(['--crate-type', 'lib']);
+            options = setCrateType(options, 'lib');
         } else {
             if (!userRequestedEmit) {
                 options = options.concat('--emit', 'asm');
             }
             if (filters.intel) options = options.concat('-Cllvm-args=--x86-asm-syntax=intel');
-            options = options.concat(['--crate-type', 'rlib']);
+            options = setCrateType(options, 'rlib');
         }
         return options;
     }

test/base-compiler-tests.ts

@@ -746,6 +746,44 @@ describe('Target hints', () => {
     });
 });
 
+describe('Rust options', () => {
+    let ce: CompilationEnvironment;
+    const executingCompilerInfo = makeFakeCompilerInfo({
+        remote: {
+            target: '',
+            path: '',
+            cmakePath: '',
+            basePath: '/',
+        },
+        semver: 'nightly',
+        lang: 'rust',
+        ldPath: [],
+        libPath: [],
+        supportsExecute: true,
+        supportsBinary: true,
+        options: '',
+    });
+
+    beforeAll(() => {
+        ce = makeCompilationEnvironment({
+            languages,
+        });
+        props.initialize(path.resolve('./test/test-properties/rust'), ['local']);
+    });
+
+    afterAll(() => {
+        props.reset();
+    });
+
+    it('does not pass `--crate-type` when specified by user', () => {
+        const compiler = new RustCompiler(executingCompilerInfo, ce);
+        const options = compiler.optionsForFilter({}, 'output.o', ['--crate-type=bin']);
+        expect(options).not.toContain('--crate-type');
+        const optionsTwoArgs = compiler.optionsForFilter({}, 'output.o', ['--crate-type', 'bin']);
+        expect(optionsTwoArgs).not.toContain('--crate-type');
+    });
+});
+
 describe('Rust overrides', () => {
     let ce: CompilationEnvironment;
     const executingCompilerInfo = makeFakeCompilerInfo({