Only use indentation to detect mismatch delimiter when the line start…

…ing with delimiter

compiler/rustc_parse/src/lexer/tokentrees.rs

@@ -107,11 +107,12 @@ impl<'a> TokenTreesReader<'a> {
             if let Some((_, open_sp, close_sp)) =
                 self.matching_delim_spans.iter().find(|(d, open_sp, close_sp)| {
                     let sm = self.string_reader.sess.source_map();
-                    if let Some(close_padding) = sm.span_to_margin(*close_sp) {
-                        if let Some(open_padding) = sm.span_to_margin(*open_sp) {
+                    if let Some(open_padding) = sm.span_to_margin(*open_sp) &&
+                        let Some(close_padding) = sm.span_to_margin(*close_sp) &&
+                            sm.is_line_before_span_empty(*open_sp) &&
+                            sm.is_line_before_span_empty(*close_sp) {
                             return delim == d && close_padding != open_padding;
                         }
-                    }
                     false
                 })
             // these are in reverse order as they get inserted on close, but

src/test/ui/parser/deli-ident-issue-1.rs

@@ -0,0 +1,27 @@
+// ignore-tidy-trailing-newlines
+//
+// error-pattern: this file contains an unclosed delimiter
+#![feature(let_chains)]
+trait Demo {}
+
+impl dyn Demo {
+    pub fn report(&self) -> u32 {
+        let sum = |a: u32,
+                   b: u32,
+                   c: u32| {
+            a + b + c
+        };
+        sum(1, 2, 3)
+    }
+
+    fn check(&self, val: Option<u32>, num: Option<u32>) {
+        if let Some(b) = val
+        && let Some(c) = num {
+        && b == c {
+            //~^ ERROR expected struct
+            //~| ERROR mismatched types
+        }
+    }
+}
+
+fn main() { } //~ ERROR this file contains an unclosed delimiter

src/test/ui/parser/deli-ident-issue-1.stderr

@@ -0,0 +1,31 @@
+error: this file contains an unclosed delimiter
+  --> $DIR/deli-ident-issue-1.rs:27:65
+   |
+LL | impl dyn Demo {
+   |               - unclosed delimiter
+...
+LL | fn main() { }
+   |                                                                 ^
+
+error[E0574]: expected struct, variant or union type, found local variable `c`
+  --> $DIR/deli-ident-issue-1.rs:20:17
+   |
+LL |         && b == c {
+   |                 ^ not a struct, variant or union type
+
+error[E0308]: mismatched types
+  --> $DIR/deli-ident-issue-1.rs:20:9
+   |
+LL |       fn check(&self, val: Option<u32>, num: Option<u32>) {
+   |                                                           - expected `()` because of default return type
+...
+LL | /         && b == c {
+LL | |
+LL | |
+LL | |         }
+   | |_________^ expected `()`, found `bool`
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0308, E0574.
+For more information about an error, try `rustc --explain E0308`.

src/test/ui/parser/deli-ident-issue-2.rs

@@ -0,0 +1,25 @@
+// ignore-tidy-trailing-newlines
+//
+// error-pattern: this file contains an unclosed delimiter
+#![feature(let_chains)]
+trait Demo {}
+
+impl dyn Demo {
+    pub fn report(&self,
+                a: u32,
+                b: u32,
+                c: u32) -> u32 {
+        return a + b + c;
+    }
+
+    fn check(&self, val: Option<u32>, num: Option<u32>) {
+        if let Some(b) = val
+        && let Some(c) = num {
+        && b == c {
+            //~^ ERROR expected struct
+            //~| ERROR mismatched types
+        }
+    }
+}
+
+fn main() { } //~ ERROR this file contains an unclosed delimiter

src/test/ui/parser/deli-ident-issue-2.stderr

@@ -0,0 +1,31 @@
+error: this file contains an unclosed delimiter
+  --> $DIR/deli-ident-issue-2.rs:25:65
+   |
+LL | impl dyn Demo {
+   |               - unclosed delimiter
+...
+LL | fn main() { }
+   |                                                                 ^
+
+error[E0574]: expected struct, variant or union type, found local variable `c`
+  --> $DIR/deli-ident-issue-2.rs:18:17
+   |
+LL |         && b == c {
+   |                 ^ not a struct, variant or union type
+
+error[E0308]: mismatched types
+  --> $DIR/deli-ident-issue-2.rs:18:9
+   |
+LL |       fn check(&self, val: Option<u32>, num: Option<u32>) {
+   |                                                           - expected `()` because of default return type
+...
+LL | /         && b == c {
+LL | |
+LL | |
+LL | |         }
+   | |_________^ expected `()`, found `bool`
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0308, E0574.
+For more information about an error, try `rustc --explain E0308`.

src/test/ui/parser/issues/issue-2354.rs

@@ -1,10 +1,8 @@
 fn foo() { //~ NOTE unclosed delimiter
   match Some(10) {
-  //~^ NOTE this delimiter might not be properly closed...
       Some(y) => { panic!(); }
       None => { panic!(); }
 }
-//~^ NOTE ...as it matches this but it has different indentation
 
 fn bar() {
     let mut i = 0;

src/test/ui/parser/issues/issue-2354.stderr

@@ -1,13 +1,8 @@
 error: this file contains an unclosed delimiter
-  --> $DIR/issue-2354.rs:15:52
+  --> $DIR/issue-2354.rs:13:52
    |
 LL | fn foo() {
    |          - unclosed delimiter
-LL |   match Some(10) {
-   |                  - this delimiter might not be properly closed...
-...
-LL | }
-   | - ...as it matches this but it has different indentation
 ...
 LL |
    |                                                    ^

src/test/ui/parser/parser-recovery-1.stderr

@@ -3,11 +3,6 @@ error: this file contains an unclosed delimiter
    |
 LL | trait Foo {
    |           - unclosed delimiter
-LL |     fn bar() {
-   |              - this delimiter might not be properly closed...
-...
-LL | }
-   | - ...as it matches this but it has different indentation
 ...
 LL | }
    |                                                      ^