Addressed review comments.

src/hyperfine/app.rs

@@ -65,6 +65,7 @@ fn build_app() -> App<'static, 'static> {
         .arg(
             Arg::with_name("runs")
                 .long("runs")
+                .conflicts_with_all(&["max-runs", "min-runs"])
                 .short("r")
                 .takes_value(true)
                 .value_name("NUM")

src/hyperfine/benchmark.rs

@@ -216,10 +216,13 @@ pub fn run_benchmark(
         / (res.time_real + prepare_res.time_real + shell_spawning_time.time_real))
         as u64;
 
-    let count = cmp::min(
-        cmp::max(runs_in_min_time, options.runs.min),
-        options.runs.max
-    );
+    let count = {
+        let min = cmp::max(runs_in_min_time, options.runs.min);
+
+        options.runs.max.as_ref()
+            .map(|max| cmp::min(min, *max))
+            .unwrap_or(min)
+    };
 
     let count_remaining = count - 1;
 

src/hyperfine/types.rs

@@ -79,14 +79,14 @@ pub struct Runs {
     pub min: u64,
 
     /// Maximum number of benchmark runs
-    pub max: u64,
+    pub max: Option<u64>,
 }
 
 impl Default for Runs {
     fn default() -> Runs {
         Runs {
             min: 10,
-            max: ::std::u64::MAX,
+            max: None,
         }
     }
 }

src/main.rs

@@ -148,14 +148,14 @@ fn build_hyperfine_options(matches: &ArgMatches) -> Result<HyperfineOptions, Opt
         (None, Some(max)) => {
             // Since the minimum was not explicit we lower it if max is below the default min.
             options.runs.min = cmp::min(options.runs.min, max);
-            options.runs.max = max;
+            options.runs.max = Some(max);
         }
         (Some(min), Some(max)) if min > max => {
             return Err(OptionsError::EmptyRunsRange);
         }
         (Some(min), Some(max)) => {
             options.runs.min = min;
-            options.runs.max = max;
+            options.runs.max = Some(max);
         }
         (None, None) => {}
     };