address Vineeth's comments

crates/aptos/src/move_tool/coverage.rs

@@ -170,7 +170,7 @@ fn compile_coverage(
         skip_fetch_latest_git_deps: move_options.skip_fetch_latest_git_deps,
         compiler_config: CompilerConfig {
             known_attributes: extended_checks::get_all_attribute_names().clone(),
-            skip_attribute_checks: false,
+            skip_attribute_checks: move_options.skip_attribute_checks,
             bytecode_version: fix_bytecode_version(
                 move_options.bytecode_version,
                 move_options.language_version,

third_party/move/tools/move-cli/src/base/coverage.rs

@@ -79,9 +79,11 @@ impl Coverage {
                     }) => (module, source_map),
                     _ => panic!("Should all be modules"),
                 };
-                let source_coverage = SourceCoverageBuilder::new(module, &coverage_map, source_map);
-                let t1 = source_coverage.compute_source_coverage(source_path);
-                t1.output_source_coverage(&mut std::io::stdout(), self.color, self.tag)
+                let source_coverage_builder =
+                    SourceCoverageBuilder::new(module, &coverage_map, source_map);
+                let source_coverage = source_coverage_builder.compute_source_coverage(source_path);
+                source_coverage
+                    .output_source_coverage(&mut std::io::stdout(), self.color, self.tag)
                     .unwrap();
             },
             CoverageSummaryOptions::Summary {

third_party/move/tools/move-coverage/src/bin/source-coverage.rs

@@ -45,9 +45,9 @@ struct Args {
     /// Colorize output based on coverage
     #[clap(long, default_value_t = ColorChoice::Default)]
     pub color: ColorChoice,
-    /// Provide textual indication of coverage
-    #[clap(long, default_value_t = Indicator::Explicit)]
-    pub explicit: TextIndicator,
+    /// Tag each line with a textual indication of coverage
+    #[clap(long, default_value_t = TextIndicator::Explicit)]
+    pub tag: TextIndicator,
 }
 
 fn main() {
@@ -78,9 +78,9 @@ fn main() {
         None => Box::new(io::stdout()),
     };
 
-    let t1 = source_cov.compute_source_coverage(source_path);
-    let t2 = t1
-        .output_source_coverage(&mut coverage_writer, args.color, args.indicator)
+    let source_coverage = source_cov.compute_source_coverage(source_path);
+    source_coverage
+        .output_source_coverage(&mut coverage_writer, args.color, args.tag)
         .unwrap();
 }
 

third_party/move/tools/move-coverage/src/source_coverage.rs

@@ -46,10 +46,20 @@ pub enum AbstractSegment {
     BoundedLeft { start: u32 },
 }
 
+/// Option to control use of color escape codes in coverage output
+/// to indicate source code coverage.  Unless `None`
+/// is selected, code which is covered is green, uncovered
+/// code is red.  By `Default`, color is only shown when
+/// output goes to a terminal.  If `Always`, then color
+/// escapes are included in the output even to a file
+/// or other program.
 #[derive(ValueEnum, Clone, Debug, Serialize)]
 pub enum ColorChoice {
+    /// Color is never shown
     None,
+    /// Color is shown only on a terminal
     Default,
+    /// Color is always shown
     Always,
 }
 
@@ -78,10 +88,18 @@ impl FromStr for ColorChoice {
     }
 }
 
+/// Option to control use of explicit textual indication of lines
+/// covered or not in test coverage listings.  If `On` or
+/// `Explicit` is selected, then lines with missing coverage
+/// are tagged with `-`; otherwise, they have `+`.
 #[derive(ValueEnum, Clone, Debug, Serialize)]
 pub enum TextIndicator {
+    /// No textual indicator of coverage.
     None,
+    /// Prefix each line with some code missing coverage by `-`;
+    /// other lines are prefixed with `+`.
     Explicit,
+    /// Same behavior as Explicit.
     On,
 }
 
@@ -383,6 +401,9 @@ fn merge_spans(file_hash: FileHash, cov: FunctionSourceCoverage) -> Vec<Span> {
         .filter(|loc| loc.file_hash() == file_hash)
         .map(|loc| Span::new(loc.start(), loc.end()))
         .collect();
+    if covs.is_empty() {
+        return vec![];
+    }
     covs.sort();
 
     let mut unioned = Vec::new();